24 - dc conferencessurgical research (2006), the leon wiltse award from the north american spine...

Spine Society of Australia

24th Annual Scientific Meeting

19 - 21 April 2013

Pan Pacific Perth Hotel

Acute spinal cord injury:

Current and future treatments

2424 Spine Society of Australia

c/- the Australian Orthopaedic Association

Level 12 | 45 Clarence Street, Sydney NSW 2000

P +61 2 8071 8000 | F +61 2 8071 8002

E [email protected] | W www.spinesociety.org.au

SSA Conference Secretariat: DC Conferences Pty Ltd

PO Box 637, North Sydney 2059

P +61 2 9954 4400 | F +61 2 9954 0666

E [email protected] | W www.dcconferences.com.au/ssa2013

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The Spine Society of Australia 24th Annual Scientific Meeting 2013

Acute spinal cord injury: Current and future treatments

2013 Proud Supporters

TITANIUM SUPPORT

GOLD SUPPORT

SILVER SUPPORT

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& CONFERENCE SATCHEL SUPPORT

AUDIO VISUAL SUPPORT


Acute spinal cord injury: Current and future treatmentsContents

2013 Proud Supporters

Contents 1

President’s Message 2

Editorial Secretary’s Report 3

Program Overview 5

Venue Floorplan 6

Exhibition Floorplan & Booth Allocations 7

Keynote Speakers 8 - 9

2013 Awards 10

General Information 11

Scientific Program - Friday 19 April 12 - 14

Scientific Program - Saturday 20 April 15 - 17

Scientific Program - Sunday 21 April 18 - 19

Poster Presentations List 20

Supporting Company Profiles 21 - 22

Supporter Advertising 23 - 27

Friday Session Abstracts:

Free Paper Session 1 | Scoliosis 29 - 34

Controversies in Spinal Cord Injury 35 - 36

Free Paper Session 2 | Trauma 37 - 42

Free Paper Session 3 | Fusion 43 - 46

Society Session 47 - 48

Saturday Session Abstracts:

Free Paper Session 4 | Clinical 49 - 54

Symposium: Biology of Spinal Cord Preservation & Restoration 55 - 58

Free Paper Session 5 | Biomechanics 59 - 64

The Getting of Surgical Wisdom 65 - 66

Sunday Session Abstracts:

Free Paper Session 6 | Lumbar 67 - 72

Free Paper Session 7 | Cervical 73 - 78

Poster Abstracts 79 - 83

Annual Meetings 84 - 86

Author Disclosure Statements 87 - 88

Poster Disclosure Statement 88

1

2013 President’s Message



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On behalf of the Spine Society of Australia, I extend a warm

welcome to all delegates attending the Society’s 24th Annual

Scientific Meeting to be held in Perth from 19 - 21 April 2013.

We welcome our keynote speakers including Professor Michael

Fehlings from the Krembil Neuroscience Centre and Toronto

Western Hospital, Canada; Associate Professor Brian Kwon

from the Department of Orthopaedics at the University of

British Columbia, Canada and Associate Professor Stuart Hodgetts

from the School of Anatomy, Physiology and Human Biology

at the University of Western Australia, Perth. We also welcome

the participation of our industry colleagues, who continually

support this society and importantly our patients.

Our 2013 meeting theme Acute spinal cord injury: Current and

future treatments will focus on surgical controversies and basic

scientific research into minimizing and recovering from spinal

cord injury.

Perth is a superb city, positioned on the banks of the beautiful

Swan River and nearby hectares of natural bushland in Kings

Park. We encourage you to get out and about to see as much

of the city as time permits. The Conference Dinner is being

held at the Royal Perth Yacht Club, located on the Swan River.

We look forward to engaging in elevated academic

presentations with dynamic debate and the sharing of

experience, in an atmosphere of respect and comradeship.

We hope you enjoy the Meeting!

Dr Peter Wilde

Organising Committee

Dr Peter Wilde

President

Dr Peter Woodland

Local Convenor�

A/Professor Graeme Brazenor

Immediate Past President

Dr Greg Malham

Secretary�

Dr Rob Kuru

Treasurer�

Dr Ralph Stanford

Scientific Program Secretary

Dr Gerald Quan

Scientific Program

24

2013 Editorial Secretary’s Report



3

Dear Members and Delegates,

The special attraction of Spine Society Meetings is the wide

spectrum of topics and professional groups that it is able

to showcase each year and this year is no different; we have

biomechanics to epidemiology to clinical material and trials.

This year’s topic is the urgency of decompression of the

traumatised spinal cord. We have a truly world class faculty

presenting all the current ideas on how to preserve spinal cord

function after trauma, from cooling to urgent surgery. As we

are on the threshold of being able to judge its worth, the role

of urgent surgery will be debated.

The Getting of Surgical Wisdom session was popular last year

and continues this year with contributions from senior and

well respected surgeons.

The Society will this year demonstrate the public advocacy

role that it has taken on recently. This work has entailed

hours of behind the scenes report writing and lobbying by

dedicated members of the executive and others. The Society

is proud of its achievement regarding cervical disc arthroplasty

and is keenly aware that we should continue to provide

leadership in the arena of public health and spinal care. To

this end there will be presentations on how the ‘cervical disc

was won’ and ideas on establishing national databases on

spinal surgery and primary tumours of the spine.

The health of our Society is strengthened by the participation

of its members and I encourage you all to come and ask

questions of the speakers.

Dr Ralph Stanford

24



5

Program Overview

Friday 19 April 2013 Saturday 20 April 2013 Sunday 21 April 2013

10.00 Morning Tea | Exhibition Area, Golden Ballroom 10.00 Morning Tea | Foyer 3

12.30pm Lunch | Exhibition Area, Golden Ballroom 12.15pm Lunch | Foyer 3

3.00pm Afternoon Tea | Exhibition Area, Golden Ballroom

8.30am Conference Opening

8.45am FREE PAPER SESSION 1

Scoliosis

Chair | Bryan Ashman


Clinical

Chair | Richard Williams

10.30am Controversies in

spinal cord injury

Chair | Brian Freeman

Dr Ralph Stanford

Prof Michael Fehlings

A/Prof Brian Kwon

5.15 - 7.15pm Welcome ReceptionExhibition Area, Golden BallroomPan Pacific Perth Hotel

7.00 - 11.00pm Conference DinnerRoyal Perth Yacht ClubAustralia II Drive, Crawley

3.30pm The Getting of

Surgical Wisdom

Chair | Ralph Stanford

Dr Peter Woodland

Dr Matthew Scott-Young

Dr William Sears

Dr Peter Moloney

4.30 - 6.00pm SSA Business Meeting


Lumbar

Chair | Rob Kuru


Cervical

Chair | Justin Pik

11.45am Award Presentations

12.15pm Conference close

3.30pm FREE PAPER SESSION 3

Fusion

Chair | Claire Jones

4.30pm Society Session

Chair | Peter Wilde

A/Prof Graeme Brazenor

Dr Michael Johnson

A/Prof Richard Williams


Trauma

Chair | Jonathon Ball


Biomechanics

Chair | Mark Pearcy

10.30am Symposium:

Biology of spinal cord

preservation & restoration

Chair | Peter Wilde

A/Prof Stuart Hodgetts

A/Prof Brian Kwon

Dr Michael Edel

Prof Michael Fehlings

Dr Peter Batchelor

All sessions will be held in the Grand River Ballroom (See detailed program starting page 12)

Pan Pacific Perth Hotel | Level 1 Floorplan



6

Plenary Sessions

Grand River Ballroom

Industry Exhibition

Golden BallroomFoyer 1

Foyer 3

Foyer 2

SpeakerPrep Room(Pilbara)

Registration

LiftLobby

Exhibition Floorplan

Exhibition Booth Allocations



7

1

2

3

4

5

15

14

13

12

22 21 20 19 18 17 16

35 36 6 7 8 9 10 11

23 26

24 25

27 30

28 29

31 34

32 33

Booths 1, 2 National Surgical

Booth 3 Device Technologies

Booth 4 MD Solutions

Booth 5 Australian Orthotic Technologies

Booth 6 Medyssey

Booth 7 Global Orthopaedic Technology

Booth 8 Signature Spine + Joint

Booth 9 Anatomics

Booth 10 Endocorp

Booth 11 KH NxGen

Booths 12, 13, 14, 15, 36 LifeHealthcare

Booth 16 Orthotech

Booths 17, 18 Brainlab

Booths 19, 20 CR Kennedy

Booths 21, 22 Stryker

Booths 23, 24, 25, 26 Medtronic

Booths 27, 28, 29, 30 DepuySynthes

Booths 31, 34 Zimmer

Booths 32, 33 Globus Medical

Booth 35 Spirit Spine

Trestle table Woodslane

Golden Ballroom | Level 1 | Pan Pacific Perth Hotel

International Keynote Speakers



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Professor Michael Fehlings MD PhD FRCSC FACS

Dr Fehlings is the Medical Director of the Krembil Neuroscience

Center and heads the Spinal Program at Toronto Western

Hospital. He is also a Professor of Neurosurgery at the University

of Toronto, holds the Halbert Chair in Neural Repair and

Regeneration, is a Scientist at the McEwen Centre for Regenerative

Medicine and a McLaughlin Scholar in Molecular Medicine.

In the fall of 2008, Dr Fehlings was appointed the inaugural Director of the University of Toronto

Neuroscience Program and Co-Director of the newly formed University of Toronto Spinal Program.

Dr Fehlings combines an active clinical practice in complex spinal surgery with a translationally

oriented research program focused on discovering novel treatments for spinal cord injury. This is

reflected by the publication of over 350 peer-reviewed articles chiefly in the area of spinal cord

injury and complex spinal surgery. Dr Fehlings leads a multi-disciplinary team of researchers which

is examining the application of stem cells, nanotechnology and tissue engineering for spinal cord

repair and regeneration. He is also a principal investigator in the Christopher and Dana Reeve

Foundation North American Clinical Trials Network, co-chair of the internationally renowned Spine

Trauma Study Group and leads several international clinical research efforts through AOSpine.

Dr Michael Fehlings has received numerous prestigious awards including the Gold Medal in

Surgery from the Royal College of Physicians and Surgeons (1996), nomination to the Who’s

Who list of the 1000 most influential scientists of the 21st century (2001), the Lister Award in

Surgical Research (2006), the Leon Wiltse Award from the North American Spine Society for

excellence in leadership and / or clinical research in spine care (2009) and the Olivecrona

Award (2009) from the Karolinska Institute in Stockholm, Sweden (known as the “Nobel Prize

of Neuroscience”) for his important contributions in spinal cord injury.

Active in many medical societies, Dr Fehlings is also a member of journal editorial boards

including Journal of Neurosurgery: Spine (Past-Chairman Editorial Board), Journal of Neurotrauma

and Spine where he holds the position of Deputy Editor. His commitment to patients with

neurotrauma is further reflected in his volunteer work for ThinkFirst, a charitable organization

which is focused on preventing brain and spinal cord injuries in children.

International Keynote Speakers

Local Keynote Speaker



9

Associate Professor Brian Kwon MD PhD FRCSC

Dr Kwon is an Associate Professor in the Department of

Orthopaedics at the University of British Columbia and the

Canada Research Chair in Spinal Cord Injury. He is a spine

surgeon at Vancouver General Hospital and a research scientist

at the International Collaboration on Repair Discoveries (ICORD).

As a surgeon-scientist, he is particularly interested in the

bi-directional process of translational research for spinal cord injury. He has worked extensively

on establishing biomarkers of human SCI, preclinical models for novel therapeutic strategies, and

a framework for how promising therapies for SCI should be evaluated prior to translation into

human patients.

Associate Professor Stuart Hodgetts

Dr Stuart Hodgetts is currently a Research Associate Professor at

the Spinal Cord Repair Laboratory, within the School of Anatomy

and Human Biology, University of Western Australia (UWA). He has

extensive knowledge and expertise in cell based transplantation

therapies and has been devoted to this area of research since

1998. Previous postdoctoral work includes 2.5 years at Oklahoma

Medical Research Foundation, USA, in immunological gene transcription and 7 years with the

Muscle Research Team at the School of Anatomy and Human Biology, (ANHB), University of

Western Australia, working on myoblast transfer therapy for Duchenne muscular dystrophy.

In 2003, Dr Hodgetts began collaborating with Dr Giles Plant, changing fields to apply his

expertise to spinal cord repair. He is particularly interested in the use of adult mesenchymal

human bone marrow stromal stem cells (hBMSC) and also the application of immune modulation

of the host response to improve donor cell survival in treatments for spinal cord repair.

With Dr Plant now based at Stanford University (Calif, USA), Dr Hodgetts has taken the helm

of the Spinal Cord Repair Laboratory and added immuno-modulation techniques to the suite of

combinatorial therapies (including hBMSC transplantation) known to trigger neuro-regeneration

and functional recovery after SCI. Dr Hodgetts was awarded the inaugural NRP Mid-Career

Research Fellowship to support and enable expansion of his work in SCI during 2011-2013.

SPINAL RESEARCH AWARD Supported by

ROB JOHNSTON AWARD Supported by

BEST PAPER AWARD Supported by

BEST POSTER AWARD Supported by

ALASTAIR ROBSON AWARD Supported by

2013 Awards



10

24

General Conference Information



11

The conference registration desk is located in Foyer 2, Level 1 | Pan Pacific Hotel

Opening Hours: Thursday 18 April 2.00pm - 5.00pm

Friday 19 April 7.30am - 7.15pm

Saturday 20 April 7.30am - 5.00pm

Sunday 21 April 7.30am - 12.30pm

Welcome Reception

Friday 19 April | 5.15pm - 7.15pm | Golden Ballroom | Level I, Pan Pacific Hotel

Conference Dinner

Saturday 20 April | 7.00pm - 11.00pm

Royal Perth Yacht Club | Australia II Drive, Crawley

Coaches from the Pan Pacific Hotel will depart from 6.30pm

The Conference Dinner is included in the registration fee for full registrants. Should you

wish to purchase a ticket or if you selected to attend but no longer wish to, please visit the

registration desk as soon as possible. The Dinner attendee list is displayed near the desk.

The Speaker Preparation area is located in the Pilbara Room on Level 1 of the Pan Pacific

Hotel. All presenters must check-in at the speaker room at least 2 hours prior to the start of

their session time. Presentations must be brought on either a USB memory stick or CD.

All delegates are provided with a name badge included in the registration pack. Delegates

are required to wear their name badges at all times throughout the Conference as this

badge is your official pass to sessions, teas and lunches.


Royal Perth Yacht Club

REGISTRATION

SOCIAL SESSIONS

SPEAKER

PREPARATION ROOM

NAME BADGES



12

Conference Program | FRIDAY 19 APRIL 2013 Sessions to be held in Grand River Ballroom

8.30am CONFERENCE OPENING

Peter Wilde

8.45 - 10.00am FREE PAPER SESSION 1 | SCOLIOSIS See abstracts pages 29 - 34

Chair | Bryan Ashman

8.45 1.1 Segmental torso masses and coronal plane joint torques in the adolescent scoliotic spine

Bethany Keenan

8.53 1.2 The influence of idiopathic scoliosis on annulus fibrosus: Mechanical properties

Celina Pezowicz

9.01 1.3 Inter-vertebral rotational deformity after endoscopic anterior scoliosis correction may

contribute to rib hump recurrence after two years

Eric Huang

9.09 DISCUSSION

9.25 1.4 The spinecor brace in the treatment of scoliosis: The Perth experience

Aravind Kumar

9.33 1.5 A systematic review of chiropractic treatment of scoliosis

Jeb McAviney

9.41 DISCUSSION

10.00am Morning Tea | Exhibition Area, Golden Ballroom

10.30 - 12.30pm CONTROVERSIES IN SPINAL CORD INJURY See abstracts pages 35 - 36

Chair | Brian Freeman

10.30 Decompression of the spinal cord at our convenience

Ralph Stanford

11.00 Timing of surgical decompression of traumatic spinal cord injury is critical to outcome

Michael Fehlings

11.30 DISCUSSION - Panel and audience

11.50 Central Cord Syndrome

Brian Kwon

12.20pm DISCUSSION - Panel and audience



13


12.30 Lunch | Exhibition Area, Golden Ballroom

1.30 - 3.00pm FREE PAPER SESSION 2 | TRAUMA See abstracts pages 37 - 42

Chair | Jonathon Ball

1.30 2.1 Early predictors of functional disability following spine trauma: A Level 1 Trauma Center Study

Jin Tee

1.38 2.2 Surgical management of post traumatic syrinx: An audit

Girish Nair

1.46 2.3 Percutaneous vertebroplasty: A first line treatment in traumatic nonosteoporotic compression

Hossam El Noamany

1.54 DISCUSSION

2.09 2.4 Predictors of stroke and mortality following blunt carotid and vertebral artery injury

at a single trauma centre

Yagnesh Balasubramani

2.17 2.5 Traumatic facet joint dislocations in Western Australia

Vivek Eranki

2.25 2.6 Lateral mass and facet joint injuries of the subaxial cervical spine: Assessment of accuracy

and interobserver agreement using plain radiographs and computed tomography

Brian Freeman

2.33 2.7 Audit of management of Traumatic Central Cord Syndrome

Girish Nair

2.41 DISCUSSION

3.00 Afternoon Tea | Exhibition Area, Golden Ballroom



14


3.30 - 4.30pm FREE PAPER SESSION 3 | FUSION See abstracts pages 43 - 46

Chair | Claire Jones

3.30 3.1 Actifuse is comparable to infuse in achieving fusion

Paul Licina

3.38 3.2 Biological performance of a polycaprolactone-based scaffold plus recombinant human

morphogenetic protein-2 (RHBMP-2) in an ovine thoracic interbody fusion model

Mostyn Yong

3.46 3.3 Biomechanical characteristics of an integrated cervical interbody fusion device

Leonard Voronov

3.54 3.4 Maintenance of segmental lordosis and disc height in standalone and instrumented extreme

lateral interbody fusion (XLIF)

Gregory Malham

4.02 DISCUSSION

4.30 - 5.15pm SOCIETY SESSION See abstracts pages 47 - 48

Chair | Peter Wilde

4.30 MSAC: Getting government approval for new spinal technology in the ‘Lucky Country’

Graeme Brazenor

4.45 Why do we need a spine registry?

Michael Johnson

5.00 A primary spinal tumour database: International collaboration on surgical outcomes and survival

Richard Williams

5.15 - 7.15pm WELCOME RECEPTION Exhibition Area | Golden Ballroom, Pan Pacific Perth Hotel



15

Conference Program | SATURDAY 20 APRIL 2013 Sessions to be held in Grand River Ballroom

8.30 - 10.00am FREE PAPER SESSION 4 | CLINICAL See abstracts pages 49 - 54

Chair | Richard Williams

8.30 4.1 Bone scans are reliable in identifying lumbar disc and facet pathology

Gregory Malham

8.38 4.2 Co-registration of isotope bone scan with CT and MR images in the investigation

of spinal pathology

Graeme Brazenor

8.46 4.3 Establishment of a novel in vivo mouse model of spinal cancer-causing, evolving paraplegia

Gerald Quan

8.54 DISCUSSION

9.15 4.4 What is the most consistent measure of thoracolumbar spinal sagittal balance?

An analysis of healthy volunteers aged 20-45

Peter Wilson

9.23 4.5 Relationship between depression and acute low back pain at first medical consultation,

three, and six weeks of primary care

Markus Melloh

9.31 4.6 Bridging the gap between treatment effectiveness and patient outcomes

Richard Kahler

9.39 DISCUSSION

10.00am Morning Tea | Exhibition Area, Golden Ballroom



16


10.30am SYMPOSIUM: See abstracts pages 55 - 58

- 12.30pm BIOLOGY OF SPINAL CORD PRESERVATION AND RESTORATION

Chair | Peter Wilde

10.30 Studies in transplantation therapies for SCI: Combinatorial approaches using purified multipotent hMPCs

isolated from SCI patients, anti-scarring agents, iPSCS and a look to the future

Stuart Hodgetts

10.48 Cell therapies: Stem cells, schwann cells, and olfactory ensheathing cells

Brian Kwon

11.06 Moving iPS cell technology closer to the clinic

Michael Edel

11.24 DISCUSSION

11.39 Neuroprotection of the injured spinal cord: Update on the Translational Pipeline

Michael Fehlings

11.57 Immediate cooling and emergency decompression for treatment of SCI

Peter Batchelor

12.15pm DISCUSSION

12.30 Lunch | Exhibition Area, Golden Ballroom

1.30 - 3.00pm FREE PAPER SESSION 5 | BIOMECHANICS See abstracts pages 59 - 64

Chair | Mark Pearcy

1.30 5.1 Biomechanical comparison of anterior and lateral plating after interbody fusion using a

novel synthetic spine model

Jonathon Ball

1.38 5.2 The effect of testing protocol on immature bovine thoracic spine segment stiffness

Nabeel Sunni

1.46 5.3 Evaluation of synthetic functional spine unit: Pure Moment Cycle Test

Tian Wang

1.54 DISCUSSION



17


FREE PAPER SESSION 5 continued

2.15 5.4 The effect of the intervertebral disc hydration on spinal biomechanics

Tian Wang

2.23 5.5 Microtensile properties of individual fibre bundles in healthy and degenerate human anulus fibrosus

John Costi

2.31 5.6 Does combined compression, flexion and axial rotation place the disc at risk of posterolateral

herniation? Measurement of 3D lumbar intervertebral disc internal strains during repetitive loading

John Costi

2.39 DISCUSSION

3.00pm Afternoon Tea | Exhibition Area, Golden Ballroom

3.30 - 4.30pm THE GETTING OF SURGICAL WISDOM See abstracts pages 65 - 66

Chair | Ralph Stanford

3.30 Two Young Ladies

Peter Woodland

3.45 Matthew Scott-Young

4.00 PLIF: Risky business or just another learning curve?

William Sears

4.15 Thoraco lumbar junction: Stop sign or proceed with caution?

Peter Moloney

4.30 - 6.00pm Business Meeting

7.00 - 11.00pm CONFERENCE DINNER | Royal Perth Yacht Club, Australia II Drive, Crawley



18

Conference Program | SUNDAY 21 APRIL 2013 Sessions to be held in Grand River Ballroom

8.30 - 10.00am FREE PAPER SESSION 6 | LUMBAR See abstracts pages 67 - 72

Chair | Rob Kuru

8.30 6.1 Microsurgical decompression with coflex interspinous dynamic stabilization for treating lumbar

degenerative stenosis

Hossam Elnoamany

8.38 6.2 Influence of previous conservatve treatment interval on outcomes following decompressive

surgery for lumbar disc herniation

Thomas Zweig

8.46 6.3 The viscoelastic LP-ESP lumbar disc prosthesis with 6 degrees of freedom:

A prospective study of 120 patients with 2 years minimum follow-up

Jean Yves Lazennec

8.54 DISCUSSION

9.15 6.4 Is there an association between abdominal muscle morphology and degenerative spondylolisthesis?

Petar Tcherveniakov

9.23 6.5 Histological characterisation of trabecular bone of the l4 lumbar spinous process in female

patients undergoing decompressive laminectomy (preliminary data)

Mohammad-reza Zarrinkalam

9.31 6.6 The pathophysiology of modic (endplate) changes in the human lumbar spine:

Is the osteocyte lacunar cell network involved?

Julia Kuliwaba

9.39 DISCUSSION

10.00am Morning Tea | Foyer 3



19

Conference Program | SUNDAY 21 APRIL 2013 Sessions to be held in Grand River Ballroom

10.30 - 12.00noon FREE PAPER SESSION 7 | CERVICAL See abstracts pages 73 - 78

Chair | Justin Pik

10.30 7.1 The role and safety of the sitting position in instrumented cervical surgery

Calvin Gan

10.38 7.2 Cervical spinal sagittal alignment: An analysis of young, asymptomatic volunteers

Peter Wilson

10.46 DISCUSSION

11.00 7.3 Effect of PLL resection on the stability of cervical disc arthroplasty

Avinash Patwardhan

11.08 7.4 Incidence of adjacent level osteophytes after anterior cervical discectomy and fusion

using non-plate fixation

Aravind Kumar

11.16 7.5 Anterior fixation and reconstruction for subaxial cervical spinal injuries: Reasons for failure

Navin Verghese

11.24 DISCUSSION

11.45 AWARD PRESENTATIONS

12.15pm Conference close

12.15 Lunch | Foyer 3



20

Poster Presentations

241. Jin Tee

Epidemiological trends of spine trauma:

An Australian Level 1 Trauma Centre Study

2. Nathan Myhill

Cervical spinal cord injury at the Victorian Spinal Cord

Injury Service: The last decade

3. Kevin Singer

Non-invasive lumbar spine movement: Validation of the

Motionstar TM 3D Electromagnetic Tracking System and

preliminary evidence

4. Aravind Kumar

“PONSETI” for congenital kyphosis

5. Hideyuki Doi

The less-invasiveness of the cervical posterolateral

approach for pedicle screw fixation using a navigation

system

6. Nicholas Maartens

Myelopathy from extensive spinal ganglioneuromas

7. Takamitsu Tokioka

Surgical procedures of anterior transarticular fixation of

atlantoaxial joint using ISO-C 3D navigation system

See abstracts pages 79 - 83

Depuy / Synthes DePuy Synthes offers an unparalleled

breadth of products, services and educational support in the

areas of spine, trauma, neurosurgery, joint reconstruction, sports

medicine, craniomaxillofacial, power tools and biomaterials.

To better support you and your patients, we aim to be agile

and well equipped to meet the needs of our rapidly evolving

healthcare environment.

At Spine Society Australia’s Annual Scientific Meeting this year,

we invite you to explore our expanded product range, meet

our team and find out how we can best support you.

LifeHealthcare LifeHealthcare is a leading Australian

and New Zealand medical device company that delivers the

best technologies through the best people in the industry.

Since our inception, we have been successful in establishing a

leadership position in key therapeutic areas through focus and

clinical expertise. The company now employs over 120 people

throughout Australia and New Zealand. While the technology

we bring to the market is a cornerstone of our achievements

to date, our real success has been delivered through the

quality of our people and partners.

In particular, LifeHealthcare is synonymous with spine surgery

and has set the standard within the Australian market. Since

introducing the first pedicle screw back in 1991, LifeHealthcare

now leads the industry with innovations across lumbar

degenerative disc disease, cervical disc herniation, spinal

fractures, and spinal stenosis. Products range from screw

based fusion systems, to dynamic stabilisation in both the

cervical and lumbar spine.

Zimmer Zimmer is a manufacturer of orthopaedic

reconstructive, spinal and trauma devices, dental implants and

related orthopaedic surgical products. Zimmer has operations

in more than 25 countries around the world and sells products

in more than 100 countries. Our mission is to restore mobility,

alleviate pain and improve the quality of life for patients

around the world. We are supported in that mission by the

efforts of more than 8,500 employees worldwide. For further

information contact David Le Lievre on 0419 480 124 or visit

us at booths 31 & 34.



21

Supporting Company Profiles

24

Medtronic At Medtronic, we're committed to innovatingfor life by pushing the boundaries of medical technology and

changing the way the world treats chronic disease. To do that,

we're thinking beyond products and beyond the status quo -

to continually find more ways to help people live better, longer.

Stryker Stryker is one of the world’s leading medical

technology companies and is dedicated to helping healthcare

professionals perform their jobs more efficiently while enhancing

patient care. The Company offers a diverse array of innovative

medical technologies including reconstructive implants, medical

and surgical equipment, and neurotechnology and spine

products to help people lead more active and satisfying lives.

For information about Stryker, please visit www.stryker.com.

Device Technologies Founded in 1992, Device

Technologies is an established distributor of quality and

technologically-advanced, capital equipment and consumables.

The company is Australian owned and employs more than 450

healthcare specialists and support staff.

All products are professionally supported by highly qualified

Product Managers and Specialist Representatives, trained to

work in surgical and operating room environments. Clinical

Educators provide accredited training, in-servicing and ongoing

clinical support. Qualified Technical Service personnel service

and maintain our extensive range of capital equipment. Our

Regulatory Affairs Division ensures all products are correctly

listed with the TGA. Our Mission:To deliver superior health

outcomes by providing patient access to the best medical

systems available worldwide.

NuVasive NuVasive® is an innovative medical device

company focused on developing minimally disruptive surgical

products and procedures for the spine. Our mission is to

improve the lives of patients who suffer from debilitating

back, neck, or leg pain by creating cutting-edge products and

procedures that revolutionize spine surgery through focusing

on Speed of Innovation,® Absolute Responsiveness,® and

superior clinical results. NuVasive has over 75 products

spanning lumbar, thoracic, cervical applications, and neuro

monitoring services as well as a biologics portfolio. Our

products have been used in thousands of spine surgeries.

NuVasive is the third-largest spine company in the US, and

the fourth-largest globally.



22

Supporting Company Profiles

24

TM ArdisTM Interbody System

• TrabecularMetal™withupto80%porosityandosteoconductivescaffoldforsofttissuevascularisationandboneyingrowth.• Highcoefficientoffrictionhelpsguardagainstmigrationandexpulsion,whilelowmodulusofelasticitypreventsstress shieldingformorenormalloadtransfer.• Anatomicalshapewithself-distractingnoseandconvexgeometrysuitableforawiderangeofMISandopenprocedures.• Withover15yearsofclinicalexperienceTrabecularMetalhasbeenutilisedinmorethan800,000surgeriesworldwide1.

ZimmerPtyLtd ZimmerNewZealandLimited Unit1-2,1SkylinePlace 210KhyberPassRoad FrenchsForestNSW2086 GraftonAuckland Australia NewZealand Tel:+61299505400Fax:+61299751438 Tel:+6499255200Fax:+6493685360www.zimmer.com.au www.zimmer.co.nz ©2013ZimmerPtyLtd

Reference1InternalZimmerResearch

For further information about Zimmer Spine contact David Le Lievre on [email protected] or 0419 480 124, otherwise visit us at booths 31 & 34.

_8342_TM Ardis A4 ad.indd 1 4/02/13 12:59 PM

NIM-ECLIPSE® System

CD HORIZON® SOLERA® Spinal System

Bone Graft

CRESCENT™

Spinal System – PEEK*

O-arm™ Imaging System

Midline Access Instruments

MAST QUADRANT™

Retractor

*The NIM-ECLIPSE® System is manufactured by Medtronic Xomed, Inc. Distributed by Medtronic Sofamor Danek USA, Inc. **Interbody implants are to be used with autogenous bone graft

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BOOTH 3Spine Society of AustraliaAnnual Scientific Meeting

19th - 21st April | Perth

28

FRIDAY 19 APRIL 2013The Spine Society of Australia 24th Annual Scientific Meeting 2013


Notes and Questions

Free PaperSession 1

SCOLIOSISFriday 19 April | 8.45am - 10.00am


S e s s i o n A b s t r a c t s

24

29

8.45am | 1.1

SEGMENTAL TORSO MASSES AND CORONAL

PLANE JOINT TORQUES IN THE ADOLESCENT

SCOLIOTIC SPINE

*Keenan BE,1, 2 Izatt MT,1, 2 Askin GN,1 Labrom RD,1 Pettet GJ,2

Pearcy MJ,1, 2 Adam CJ 1, 2

1. QUT / Mater Paediatric Spine Research Group,

Queensland University of Technology, Mater Misericordiae Health

Services, Brisbane, QLD Australia

2. Institute of Health and Biomedical Innovation, Queensland

University of Technology, Brisbane, QLD Australia

INTRODUCTION

Calculating segmental (vertebral level-by-level) torso masses in

Adolescent Idiopathic Scoliosis (AIS) patients allows the

gravitational loading on the scoliotic spine during relaxed standing

to be determined. This study used CT scans of AIS patients to

measure segmental torso masses and explores how joint moments

in the coronal plane are affected by changes in the position of

the intervertebral joint’s axis of rotation; particularly at the apex

of a scoliotic major curve.

METHODS

Existing low dose CT data from the Paediatric Spine Research

Group was used to calculate vertebral level-by-level torso

masses and joint torques occurring in the spine for a group of

20 female AIS patients (mean age 15.0 ± 2.7 years, mean Cobb

angle 53 ± 7.1°). Image processing software, ImageJ (v1.45 NIH

USA) was used to threshold the T1 to L5 CT images and

calculate the segmental torso volume and mass corresponding

to each vertebral level. Body segment masses for the head, neck

and arms were taken from published anthropometric data. 1

Intervertebral (IV) joint torques at each vertebral level were

found using principles of static equilibrium together with the

segmental body mass data. Summing the torque contributions

for each level above the required joint, allowed the cumulative

joint torque at a particular level to be found. Since there is some

uncertainty in the position of the coronal plane Instantaneous

Axis of Rotation (IAR) for scoliosis patients, it was assumed the

IAR was located in the centre of the IV disc. A sensitivity analysis

was performed to see what effect the IAR had on the joint

torques by moving it laterally 10mm in both directions.

RESULTS

The magnitude of the torso masses from T1-L5 increased

inferiorly, with a 150% increase in mean segmental torso mass

from 0.6kg at T1 to 1.5kg at L5. The magnitudes of the calculated

coronal plane joint torques during relaxed standing were typically

5-7 Nm at the apex of the curve, with the highest apex joint

torque of 7Nm being found in patient 13. Shifting the assumed

IAR by 10mm towards the convexity of the spine, increased the

joint torque at that level by a mean 9.0%, showing that calculated

joint torques were moderately sensitive to the assumed IAR

location. When the IAR midline position was moved 10mm away

from the convexity of the spine, the joint torque reduced by a

mean 8.9%.

CONCLUSION

Coronal plane joint torques as high as 7Nm can occur during

relaxed standing in scoliosis patients, which may help to explain

the mechanics of AIS progression. This study provides new

anthropometric reference data on vertebral level-by-level torso

mass in AIS patients which will be useful for biomechanical

models of scoliosis progression and treatment. However, the CT

scans were performed in supine (no gravitational load on spine)

and curve magnitudes are known to be smaller than those

measured in standing. 2

REFERENCES

1. 2009 WINTER DA.

Biomechanics and Motor Control of Human

Movement, Wiley & Sons Inc., Canada.

2. 1985 TORELL G et al.

Standing and supine Cobb measures in girls with idiopathic

scoliosis. Spine 10: 425-27.



30

FREE PAPER SESSION 1 | Scoliosis • Chair Bryan Ashman • 8.45am - 10.00am

8.53am | 1.2

THE INFLUENCE OF IDIOPATHIC SCOLIOSIS ON

ANNULUS FIBROSUS MECHANICAL PROPERTIES

*Pezowicz CA,1 Zak M,1 Glowacki M 2

1. Division of Biomedical Engineering and Experimental

Mechanics, Wroclaw University of Technology, Poland

2. Department of Paediatric Orthopaedics, Karol Marcinkowski

University of Medical Sciences, Poland

INTRODUCTION

The mechanical properties of the intervertebral disc are

determined by the architecture of collagen fibres in the annulus

fibrosus (Pezowicz et. al., 2005). Deformities of the spine, in

particular idiopathic scolioses, lead to a number of structural

changes of the intervertebral disc that affect the functioning of

the entire spine. There is a lack of studies of the mechanical

properties or analyses of changes in the structure of the collagen

matrix that could shed light on the functioning of deformed

intervertebral discs. The aim of this study was analysis of the

impact of idiopathic scoliosis on the mechanical properties of the

annulus fibrosus (AF) of the intervertebral disc (IVD).

METHODS

Human IVDs were obtained from patients undergoing surgery

for idiopathic scoliosis. A total of 11 disc pieces from 6 patients

(aged 14-20 years) were used for microtensile testing. In-plane

intralamellar sections, with a nominal thickness of 45-50μm, werecut from the outer lamellae of discs using a cryostat microtome.

These sections were trimmed to leave mono-aligned areas of

tissue, which were then cut to create microtensile specimens.

The specimens were then subjected to uniaxial tensile loading

longitudinally and transversely to the main fibre directions using

a special microtensile device. The specimens were tested at a

constant rate of 0.06 mm/s until fracture.

RESULTS

As a result of the study, the characteristics were obtained for a

change of stress as a function of strain, which were used to

determine failure stress. The mean failure stress value of the

specimens stretched along the main fibre directions was 4.68±

1.61MPa and was significantly higher (p<0.01) than the mean

failure stress value of the specimens stretched across the main

fibre directions (0.51±0.27MPa). During longitudinal stretching,

loss of load-carrying capacity occurs already after about 20%

deformation (relative to the initial length of the specimen). On

the other hand, during transverse stretching, after an initial

increase in stress there is a slight but noticeable increase in stress

during the application of the tensile force.

DISCUSSION

Differences between the maximum stress values depending on

the tensile direction are consistent with previous observations

on ovine IVDs, which can also be considered as a model of a

healthy disc (Pezowicz et. al., 2005). However, the results obtained

in the present study show significantly lower values of failure

stress for scoliotic AF than in the case of ovine AF. This suggests

lower ability of the scoliotic disc to transfer loads, which is

related to changes in the AF structure, such us disorganisation of

collagen and elastic fibre networks (Yu et.al., 2005).

REFERENCES

1. PEZOWICZ CA, ROBERTSON PA, BROOM ND,

J. Anat., 2005. 207: 299-312.

2. YU J, FAIRBANK JCT, ROBERTS S, URBAN JPG,

Spine, 2005. 30:1815-1820.

Acknowledgements:

This research project is supported by grant No. NN518501139

9.01am | 1.3

INTER-VERTEBRAL ROTATIONAL DEFORMITY

AFTER ENDOSCOPIC ANTERIOR SCOLIOSIS

CORRECTION MAY CONTRIBUTE TO RIB HUMP

RECURRENCE AFTER TWO YEARS

*Huang EM,1 Askin GN,1 Labrom RD,1 Adam CJ,1, 2 Izatt MT,1, 2

Pearcy MJ 1, 2

1. QUT / Mater Paediatric Spine Research Group, Queensland

University of Technology, Mater Misericordiae Health Services,

Brisbane, QLD Australia



INTRODUCTION

Endoscopic anterior scoliosis correction has been employed

recently as a less invasive and level-sparing approach compared

with open surgical techniques. We have previously demonstrated

that during the two-year post-operative period, there was a

mean loss of rib hump correction by 1.4 . 1 The purpose of this

study was to determine whether intra- or inter-vertebral

rotational deformity during the post-operative period could

account for the loss of rib hump correction.



31


METHODS

Ten consecutive patients diagnosed with adolescent idiopathic

scoliosis were treated with an endoscopic anterior scoliosis

correction. Limited-dose computed tomography scans of the

instrumented segment were obtained post-operatively at 6 and

24 months following institutional ethical approval and patient

consent. Three-dimensional multi-planar reconstruction software

(Osirix Imaging Software, Pixmeo, Switzerland) was used to

create axial slices of each vertebral level, corrected in both

coronal and sagittal planes. Vertebral rotation was measured

using Ho’s method 2 for every available superior and inferior

endplate at 6 and 24 months. Positive changes in rotation indicate

a reduction and improvement in vertebral rotation. Intra-observer

variability analysis was performed on a subgroup of images.

RESULTS

Mean change in rotation for vertebral endplates between 6 and

24 months post-operatively was -0.26˚ (range -3.5 to 4.9˚)

within the fused segment and +1.26˚ (range -7.2 to 15.1˚) for

the un-instrumented vertebrae above and below the fusion.

Mean change in clinically measured rib hump for the 10 patients

was -1.6˚ (range -3 to 0˚). The small change in rotation within

the fused segment accounts for only 16.5% of the change in rib

hump measured clinically whereas the change in rotation between

the un-instrumented vertebrae above and below the construct

accounts for 78.8%. There was no clear association between rib

hump recurrence and intra- or inter-vertebral rotation in

individual patients. Intra-rater variability was ± 3˚.

CONCLUSIONS

Intra- and inter-vertebral rotation continues post-operatively

both within the instrumented and un-instrumented segments of

the immature spine. Rotation between the un-instrumented

vertebrae above and below the fusion was +1.26˚, suggesting

that the un-instrumented vertebrae improved and de-rotated

slightly after surgery. This may play a role in rib hump recurrence,

however this remains clinically insignificant.

REFERENCES

1. HAY D, IZATT MT, ADAM CJ, LABROM RD, ASKIN GNRadiographic outcomes over time after endoscopic anterior scoliosis correction: a prospective series of 106 patients. Spine 2009. 34(11):1176-84

2. HO EK, UPADHYAY SS, CHAN FL, HSU LC, LEONG JC. New methods of measuring vertebral rotation from computed tomographic scans. An intraobserver and interobserver study on girls with scoliosis. Spine 1993 18(9):1173-1177

9.25am | 1.4THE SPINECOR BRACE IN THE TREATMENT OF

SCOLIOSIS: THE PERTH EXPERIENCE

*Kumar A, Crameri S, Chenik D, Woodland P, Dillon D

Royal Perth Hospital, Perth, WA Australia

INTRODUCTION

Bracing is a generally accepted form of treatment for scoliosis in

skeletally immature individuals with Cobb angle of more than 20

deg. The efficacy of bracing is rather more controversial, mainly

due to issues with study design and methodology. Compliance is

also a major concern with the rigid bracing systems such as the

Boston brace. We present our experience with the SpineCor

bracing system, which is a low profile system that is also less

restrictive. This dynamic system relies on the patients’ corrective

movements and also offers rotational correction.

METHODS

This is a retrospective case-note and radiological study with

prospective data collection. Data collected include Risser scores,

Cobb angles and conversion rates to rigid braces and to surgery.

The SpineCor cohort is compared to a rigid brace cohort used

as a historical case control series. All patients were treated in

one institution by 2 surgeons and were under the care of 1

orthotist throughout their duration of treatment.

RESULTS

A total of 29 patients have completed treatment with this brace

at the time of this study. Risser score at start of treatment was 2

or less in almost all patients. Average time in brace was 16 months

(4-38). Only 4 out of the 29 patients went on to progress by more

than 5 deg (13.8%). 5 patients ended up requiring surgery (17.2%).

9 patients were converted to a rigid brace and 3 of these went

on to have a surgical correction and fusion. The average correction

in the group that was treated exclusively with the SpineCor

brace was a decrease in Cobb angle of 5.6 deg (-26 to 8).

CONCLUSIONS

Our progression rate of 13.8% compares favourably with the

expected progression rate of 68% in this group. Our surgical

conversion rate was also low at 17.2% - which compares

favourably to the expected rate of 60%. Our control group,

which was treated with a modified Boston type rigid brace

showed a progression of more than 5 deg in 13 out of 32

patients (40.6%) and a surgical conversion rate of 11 patients

(34.4%). We conclude that the SpineCor brace is an effective

device for the brace management of scoliosis in a select group of

patients. It is also potentially less restrictive and hence could

encourage better compliance rates.

32




9.33am | 1.5A SYSTEMATIC REVIEW OF CHIROPRACTIC

TREATMENT OF SCOLIOSIS

Jeb McAviney

ScoliCare, Sydney, NSW Australia

INTRODUCTION

Chiropractors often advocate interventions such as spinal

manipulative therapy (SMT) and chiropractic rehabilitation

programs for the treatment of scoliosis. The purpose of this

review was to evaluate the evidence supporting these

approaches.

METHODS

A systematic literature search was performed of Medline,

CINAHL and Google Scholar using the search terms, “chiropractic”

and scoliosis”, “chiropractic treatment and scoliosis”, “spinal

manipulation and scoliosis”.

RESULTS

Two systematic reviews were found which showed no strong

evidence.1 One randomised control trial was found with a sample

of six patients and no follow up. 2 There were two prospective

cohorts, three case series and ten case studies. None of the

studies used the Scoliosis Research Society (SRS) inclusion

criteria for non-operative studies, and only two studies had post

treatment follow-up.

Two themes of treatment were seen:

1. Studies involving chiropractic SMT as the primary intervention

2. Studies using SMT in combination with specific rehabilitation.

Of the studies where manipulation was the primary intervention,

some case reports reported reduction in Cobb angle. However,

the strongest study was a cohort time-series trial that did not

support the findings of the case reports. 3

From the studies using a chiropractic rehabilitation treatment,

three retrospective case reviews reported reductions in the

Cobb angle at the end of treatment. One had follow up at 24

months showing stable results. 4 However, none of the studies

included adolescent or juvenile patients at risk of progression.

DISCUSSION

There is a lack of quality evidence for chiropractic interventions

in the treatment of scoliosis. The best evidence suggests SMT does

not influence the progression of scoliosis. It is reported that

chiropractic rehabilitation programs may influence Cobb angle.4, 5, 6

However these results mostly had no follow-up and therefore

could have been temporary. In the one study with follow-up, the

results were in patients that were not at risk of significant

progression. The relevance of Cobb angle reduction in non-

progressive cases is questionable. Rehabilitation programs that

focus only on Cobb angle reductions do not address the

biomechanical issues such as sagittal balance and the quality of

life issues that often have the greatest impact on these patients.

CONCLUSIONS

Spinal manipulation is not evidenced as an effective treatment for

scoliosis. The evidence for chiropractic rehabilitation programs

for scoliosis is low. Future studies should be conducted to

understand the potential of chiropractic rehabilitation approaches.

However, until good prospective evidence exists for chiropractic

rehabilitation treatments these interventions should not be

recommended over treatments that have demonstrated better

evidence, such as bracing and surgery, particularly for patients at

risk of progression.

For chiropractors to play a role in the management of scoliosis,

they should use their role as primary health care clinicians to aid

in assessment, management, and referral in scoliosis cases.

REFERENCES

1. Manual therapy as a conservative treatment for adolescent

idiopathic scoliosis: A systematic review, Scoliosis 2008,

3:2 Negrini et al.

2. ROWE DE, et al.

Chiropractic manipulation in adolescent idiopathic scoliosis:

a pilot study. Chiropractic & Osteopathy. 2006 August

3. Effect of chiropractic intervention on small scoliotic curves in

younger subjects, C.LANTZ et al J Manipulative Physiol Ther

2001;24:385-93

4. Outcomes for adult scoliosis patients receiving chiropractic

rehabilitation: A 24-month retrospective analysis; J Chiropr Med:

Sep 2011(10:3): 179-184

5. HARRISON DE, et al.

Reduction of deformity after chiropractic biophysics mirror image

care incorporating the non-commutative property of finite

rotation angles in five patients with thoracolumbar scoliosis.

J Chiropractic Education 2006;20(1):19-20.

6. Scoliosis treatment using a combination of manipulative and

rehabilitative therapy: a retrospective case series

M MORNINGSTAR, et al, BMC Musculoskeletal Disorders, 5:32.

Published: 14 September 2004

33




34



Notes and Questions

Controversiesin Spinal Cord Injury

Friday 19 April | 10.30am - 12.30pm



24

35

10.30am

DECOMPRESSION OF THE SPINAL CORD

AT OUR CONVENIENCE

Dr Ralph Stanford

Department of Orthopaedics, Prince of Wales Hospital and

University of New South Wales, Sydney, NSW Australia

11.00am

TIMING OF SURGICAL DECOMPRESSION OF

TRAUMATIC SPINAL CORD INJURY IS CRITICAL

TO OUTCOME

Professor Michael Fehlings

Krembil Neuroscience Center, Spinal Program at Toronto Western

Hospital and Neurosurgery Department at the University of Toronto,

Ontario, Canada

11.50am

CENTRAL CORD SYNDROME

Associate Professor Brian Kwon

Department of Orthopaedics, University of British Columbia and

Spinal Surgery, Vancouver General Hospital, British Colombia, Canada

The first descriptive characterization of the acute, traumatic

central cord syndrome was initially published in 1954 by Schneider

and colleagues, as a pattern of incomplete paralysis characterized

primarily by a disproportionate motor impairment of the upper

limbs compared to the lower limbs. Associated with this are

varying degrees of sensory disturbance and bladder dysfunction.

This pattern of incomplete tetraplegia most frequently occurs in

elderly individuals with congenital and / or spondylotic stenosis of

the cervical spinal canal who suffer a hyperextension injury of

the neck. The central cord pattern of paralysis is the most

commonly observed pattern of incomplete spinal cord injury.

The optimal management of patients with acute central cord

syndrome remains controversial. Given that patients who sustain

an acute central cord injury can be of a wide age spectrum,

present with a wide variety of cervical pathology, and can suffer

very different severities of neurologic injury, defining the optimal

treatment has been extremely difficult. Complicating this is the

fact that most patients with this pattern of incomplete tetraplegia

and a stable cervical spine will experience objective neurologic

improvement over time without any surgical intervention. This

lecture will discuss the contemporary literature on this topic and

provide a perspective on its management.

36



CONTROVERSIES IN SPINAL CORD INJURY • Chair Brian Freeman • 10.30am - 12.30pm

Free PaperSession 2

TRAUMAFriday 19 April | 1.30pm - 3.00pm



24

37

1.30pm | 2.1EARLY PREDICTORS OF FUNCTIONAL

DISABILITY FOLLOWING SPINE TRAUMA:

A LEVEL 1 TRAUMA CENTER STUDY

Jin Tee

Neurosurgery Trainee, The Alfred Hospital, Melbourne, VIC Australia

STUDY DESIGN

Prospective cohort study and explicit chart review

OBJECTIVES

1. To identify early spine trauma predictors of functional disability

2. To assess management compliance to established spine

trauma treatment algorithms

SUMMARY OF BACKGROUND DATA

Identification of early spine trauma predictors of functional

disability is novel and may assist in the management of trauma

patients. Also, with significant global variation, spine trauma

treatment algorithms are essential.

METHODS

Analysis was performed on spine trauma patients from 1 May

2009 to 1 January 2011. Functional outcomes were determined

using the Glasgow Outcome Scale (GOS) at 1 year. Univariate

and multivariate regression were applied to investigate the effects

of the ISS, age, BSL, vital signs, TBI, comorbidities, coagulation

profile, neurology and spine injury characteristics. A compliance

study was performed using SLIC and TLICS algorithms.

RESULTS

The completion rate for the GOS was 58.8%. The completed

GOS cohort was 4.2 years younger in terms of mean age, had

more severe polytraumatized patients, but less patients with

severe spinal cord injuries (ASIA A, B and C) in comparison with

the uncompleted GOS cohort. Multivariate logistic regression

revealed three independent early spine trauma predictors of

functional disability with statistical significance (p<0.05). They were

1. hypotension (OR=1.98; CI=1.13-3.49)

2. hyperglycaemia (OR=1.67; CI=1.09-2.56)

3. moderate / severe traumatic brain injury

(OR=5.88; CI=1.71-20.16).

There were 305 patients with subaxial cervical spine injuries and

653 patients with thoracolumbar spine injuries. The SLIC and

TLICS compliance studies returned agreements of 96.1% and

98.9% respectively.

CONCLUSION

Early independent spine trauma predictors of functional disability

identified in a Level 1 trauma centre with high compliance to the

SLIC and TLICS algorithms were hypotension, hyperglycaemia

and moderate or severe traumatic brain injury. Spine trauma

injury variables alone were shown not to be predictive of

functional disability.

1.38pm | 2.2SURGICAL MANAGEMENT OF POST TRAUMATIC

SYRINX: AN AUDIT

*S Girish Nair, Augusto Gonzalvo, Myron Rogers

Department of Neurosurgery, Austin Hospital, Melbourne, VIC Australia

INTRODUCTION

Post traumatic syrinx (PTS) refers to the occurrence of cystic

cavities within the spinal cord secondary to previous injury to

the cord. The incidence is estimated to be 0.3 to 3% in spinal

cord injury patients. This study is a clinical audit of patients

surgically treated for post traumatic syrinx

METHODS

A retrospective study of patients with PTS who underwent

surgery by various techniques including decompressions,

duroplasties , adhesiolysis , shunts etc were done. These patients

presented with symptoms of autonomic dysfunction , dysaesthetic

pains, worsening neurological deficit or a combination of the

above. The outcome was evaluated based on the degree of

improvement of the presenting symptoms .

RESULTS

A total of 39 patients underwent surgery for PTS , this included

33 males and 6 females. Twelve of these patients had a partial

cord injury and the remainder (27) had complete cord injury.

11 patients had previously undergone instrumented fusions at

the time of presentation. The time to diagnosis post injury

ranged from 3 months to 26 years. The average no of operations

was 1.94 ( range from 1-7 operations). 30 patients showed

varying degrees of improvement

CONCLUSION

Post traumatic syrinx is often under diagnosed and accounts for

delayed neurological of functional deterioration. The interval to

development and diagnosis is variable. Majority of the patients

showed improvement, often after multiple operations . Surgical

treatments response is variable and needs to be individualised

for favourable outcome.

38



FREE PAPER SESSION 2 | Trauma • Chair Jonathon Ball • 1.30pm - 3.00pm

1.46pm | 2.3

PERCUTANEOUS VERTEBROPLASTY: A FIRST LINE

TREATMENT IN TRAUMATIC NON-OSTEOPOROTIC

COMPRESSION SPINAL FRACTURES

*Hossum El Noamany

Menoufiya University Hospital, Menoufiya, Egypt

BACKGROUND

Vertebroplasty is commonly used for osteoporotic and neoplastic

compression fractures, yet little evidence exists for its use in

traumatic non-osteoporotic compression fractures. The purpose

of this prospective cohort study is to document and evaluate the

clinical and radiological results of percutaneous vertebroplasty as

first line treatment in traumatic non-osteoporotic compression

fractures.

PATIENTS AND METHODS

Twenty three patients with traumatic non-osteoporotic

compression fractures and normal bone mineral densitometry

scores had been treated with percutaneous vertebroplasty are

included. Vertebroplasty consists in the injection of cement

(PMMA) in the damaged vertebral body to prevent further

collapse of non-osteoporotic spinal fractures. Pain was evaluated

two hours, one week, one month, 6 months, and one year post

procedure using 10-point Visual analogue Scale (VAS).

Ronald-Morris Disability Questionnaire (RDQ) scores were also

collected. A statistical analysis including a 2-tailed t test comparing

postoperative data with preoperative values. Also, medication

usage and range of mobility were evaluated as well.

RESULTS

Twenty three patients with average age 36 years and 69.5% of

them females. Significant improvement in VAS scores both at rest

and with motion and in RDQ scores (P˂ 0.05). Low rate of insignificant complications was recorded (13%). Radiological data

showed no collapse in injected vertebrae. Significant decrease in

rate of medication consumption post procedure was also

recorded (P˂ 0.05).

CONCLUSIONS

From this study it is concluded that vertebroplasty can be used

successfully as first line treatment in patients with non-osteoporotic

compression spinal fractures. It is also an effective method to

decrease pain, increase mobility, & decrease narcotic administration.

2.09pm | 2.4

PREDICTORS OF STROKE AND MORTALITY

FOLLOWING BLUNT CAROTID ANDVERTEBRAL

ARTERY INJURY AT A SINGLE TRAUMA CENTRE

*Balasubramani YV, Hwang PYK, Chan CHP, Fitzgerald MCB,

Madan A, Paul E, Rosenfeld JV

The Alfred Hospital, Melbourne, VIC Australia

INTRODUCTION

Blunt carotid and vertebral artery injuries (BCVI) are uncommon

but potentially devastating. This study was undertaken to identify

independent predictors of stroke and mortality following BCVI.

Several studies have identified risk factors for BCVI. None, however,

has specifically addressed the subgroup of patients who are at the

highest risk of developing stroke or dying. BCVI represents a

challenging disease to manage, compounded by the current lack

of consensus regarding appropriate treatment.

METHODS

Retrospective data between January 2003 and January 2012 was

obtained from the Alfred hospital’s health information system,

patient medical records and the Department of Neurosurgery’s

database. Treatments included anti-platelet, anti-coagulation,

endovascular or open surgery. TBI was categorised using the

post-resuscitation GCS and CT abnormalities. SBP was measured

upon admission to the Emergency department. Logistic regression

analysis was performed to determine the effect of age, mechanism

of injury, presenting GCS, BCVI Denver grade, affected artery,

presence of cervical spine fracture, head injury and treatment, on

the risk of developing a stroke or dying during that admission.

RESULTS

Between 2003 and 2012, 28939 patients were admitted to the

Alfred Hospital Trauma Service. Of these, 72 (0.25%) patients

sustained carotid artery injury, 82 (0.28%) vertebral artery injury

and 2 (0.007%) sustained both carotid and vertebral artery

injuries. Using logistic regression, univariate analysis revealed that

factors associated with increased risk of developing stoke after

BCVI included carotid (BCI) injury (OR =3.02 (95% CI: 1.44-6.36),

p=0.004), GCS <9 on admission (OR= 1.9 (0.93-3.97), p=0.07)

and ISS ≥15 (OR=4.74 (1.36-16.55), p=0.015). The odds of strokedecreased with upper (C1-C3) and middle (C4-C5) cervical

segment fractures (p=0.0.03 and p=0.055 respectively). After

adjusting for GCS and BCVI grade, harbouring a blunt carotid

39




artery injury had an independent association with development of

stroke (OR= 2.91 (1.32-6.46), p= 0.009).

Factors associated with increased risk of mortality on univariate

analysis were BCI (OR=3.02 (1.23-7.47), p=0.016), GCS<9

(OR= 43.71 (9.74-196.28), p<0.0001), abnormal CT brain

(OR=3.12 (1.30-7.51), p=0.011), BCVI grade 5 (OR=30.71 (3.42-

276.09), p=0.002), SBP<90 (OR=5.32 (1.47-19.28), p=0.011),

ISS≥15 (OR=8.88 (1.16-68.22), p=0.036) and stroke (OR=7.55(3.03-18.86), p<0.0001). When adjustment was performed for

BCVI grade and vessel type, treatment with aspirin was found be

significantly associated with reduced risk of mortality after BCVI

(OR= 0.04 (0.01-0.3), p=0.002).

CONCLUSION

Stroke and mortality predictors enable us to identify the at-risk

sub-population among BCVI patients. Treatment with aspirin, when

not contraindicated, in these patients reduces mortality.

2.17pm | 2.5

TRAUMATIC FACET JOINT DISLOCATIONS

IN WESTERN AUSTRALIA

*Vivek Eranki, David Dillon

Spinal Unit, Royal Perth Hospital, Perth, WA Australia

INTRODUCTION

In WA, RPH provides a statewide spinal service and accepts all

referrals from peripheral hospitals. The economies of distance in

WA means that there is a considerable time period between injury

in rural setting and enlocation at RPH. This study aims to identify

any prejudicial clinical outcomes as a consequence of this delay.

METHODS

This study retrospectively examines all facet joint dislocations that

presented to RPH between 01/01/2009 and 31/12/2011. Data

was collected on the demographics of patients, injury mechanism,

neurological assessment and times at site of injury, RPH ED and

post rehabilitation.

RESULTS

Over the three years, 42 traumatic facet joint dislocations presented

to RPH. The most common mechanism of injury was motor vehicle

accident. 65% of these MVAs occurred outside the Perth

metropolitan area and 75% of injuries took place during daytime.

In the urban group, the median time for arrival at RPH and

enlocation was 3hrs and 11hrs respectively. In the rural group, the

median time for arrival at RPH and enlocation was 13hrs and

27hrs respectively.

RURAL GROUP

URBAN GROUP

� ASIA SCORE AT SCENE

� FINAL ASIA SCORE

Graph 1:

ASIA score at scene & Final ASOA score in the rural and urban group

Graph 1 shows the progression in ASIA scores in the rural and

urban group. More patients in the urban group had a higher final

ASIA score. In the urban group, of the patients who ended up with

an ASIA score of D or E, 1 started from A, 1 from B, 2 from C and

1 from D. In the group that ended up with an ASIA score of A, only

1 patient started with a higher score of B. In the rural group, of the

patients that ended with an ASIA sore of D, 2 started with an ASIA

score of E while the other 2 started with as ASIA D. In the patients

that ended up with an ASIA A, B or C, 3 started at ASIA B and 3 as

ASIA A.

40




Graph 2 shows the progression of ASIA scores in both groups.

More patents had an improvement in their ASIA score in the urban

group to a higher level from their initial ASIA score. This lead to a

final ASIA score majority of D or E in the urban group as opposed

to A, B or C in the rural group (Graph 3)

RURAL GROUP URBAN GROUP

SITE RPH FINAL SITE RPH FINAL

Graph 2: Progression of ASIA scores in Rural and Urban groups

RURAL GROUP URBAN GROUP

� A,B,C � D,E*

Graph 3:

Final ASIA score (*excluding patients who were ASIA E throughout)

CONCLUSION

This study confirms the challenges of management of these injures

in a large geographical area where current services are confided

to a single center. Generally, facet joint dislocations with a delayed

reduction had a poorer outcome in terms of final neurological

function. We plan to draw up a protocol for enlocation of ASIA

A,B,C rural injuries such that they can be enlocated peripherally.

2.25pm | 2.6

LATERAL MASS AND FACET JOINT INJURIES

OF THE SUBAXIAL CERVICAL SPINE: ASSESSMENT

OF ACCURACY AND INTEROBSERVER AGREEMENT

USING PLAIN RADIOGRAPHS AND COMPUTED

TOMOGRAPHY

*Brian JC Freeman,3 Joost J van Middendorp,1, 2 Ben Goss,2

YH Yau,3 Richard Williams,2 Ian Cheung,2 Kristian Dalzell,3

Hamish Deverall,2 Steve Morris,2 Simon Sandler 3

1. Stoke Mandeville Spinal Foundation, National Spinal Injuries

Centre, Stoke Mandeville Hospital, Aylesbury, UK

2. AOSpine Reference Centre, Queensland University of Technology,

Brisbane QLD Australia

3. AOSpine Reference Centre, Royal Adelaide Hospital, Adelaide, SA

Australia

INTRODUCTION

While the serious consequences of missed lateral mass / facet

joint injuries of the subaxial cervical spine are well recognized,

data on the accuracy and agreement of detecting these injuries

demonstrate inconsistent reliability. The aims of this study were:

1) To assess the accuracy of detecting lateral mass and facet

joint injuries of the subaxial cervical spine from plain

radiographs and from computed tomography (CT) of the

cervico-thoracic spine.

2) To assess the interobserver reliability of radiographic

measurements including classification of injury, vertebral body

translation and articular apposition.

METHODS

Eight spinal surgeons assessed four randomly ordered sets of

30 de-identified radiological cases with and without facet joint

injuries of the subaxial cervical spine. Two surveys included plain

radiographs and two included CT images with digital imaging

software. Observers were asked to report the most caudal level

visible on the lateral radiograph, the presence or otherwise of a

facet joint injury, the level of injury, the classification of injury,

vertebral body translation and articular apposition. Morphological

characteristics and radiological measurements were assessed for

accuracy and reliability.

RESULTS

Thirty radiological cases (21 male, 9 female) were scored of

which 19 had a facet joint injury and 11 did not. Six of these 19

41




facet joint injuries were not observed on the plain radiographs.

Mean patient age at the time of injury was 47 years (range 17 to

93 years). Measures of agreement were made for visible caudal

level, the presence of injury, the level of injury and classification of

the injury morphology.

According to the Landis and Kosh criteria, only ‘moderate

agreement’ could be obtained with plain radiographs across the

spectrum of measures. ‘Substantial’ to ‘almost perfect’ agreement

was obtained when CT imaging was used.

Interobserver Visible Kappa Caudal Injury Levelstatistic Level Present of Injury Classification

Survey 1 0.536 0.43 0.48 0.29

(Plain Film)

Survey 20.557 0.53 0.55 0.32

(Plain Film)

Survey 3 (CT) - 0.73 0.71 0.55

Survey 4 (CT) - 0.76 0.77 0.51

CONCLUSIONS

Plain radiographs of the cervical spine are not reliable for the

assessment of subaxial cervical spine trauma. Computed

tomography was reliable in detection of injury and level of injury

with substantial interobserver agreement, whilst classification of

injury demonstrated moderate interobserver agreement.

2.33pm | 2.7AUDIT OF MANAGEMENT OF TRAUMATIC

CERVICAL CENTRAL CORD SYNDROME

*S Girish Nair, Thuan Tzen Koh, Gerald Quan, Augusto Gonzalvo, Lu Ton, Myron Rogers, Peter WildeDepartments of Orthopaedic Surgery and Neurosurgery,

Austin Hospital, Heidelberg, Vic, Australia

INTRODUCTIONTraumatic central cord syndrome accounts for about 9% of alltraumatic spinal cord injuries. The necessity of surgery for traumatic central cord syndrome and the timing of the same remains unclear. This study is a clinical audit of patients treatedfor traumatic central cord syndrome at the Austin Hospital, Victoria between 2002-2012.

METHODSThis study aimed to evaluate the neurological outcome of patientstreated for traumatic central cord syndrome by retrospectiveanalysis of date collected prospectively. Beside demographic data,evaluation, we assessed the influence of factors including the nature of injury, type of intervention (conservative versus operative) and timing of surgery.

RESULTSA total of 39 patients (M:F=33:6) were included. The mean agewas 55.6 years (range 16-87). They were evaluated with ASIAmotor score at admission and at one year follow up .The mostcommon radiological level of involvement was C4 /5 (28 / 39)and 14 patients (35.89%) had unstable injuries 21 patients (56.41%)of the total group were treated with operative intervention.Evaluation of data demonstrated that there is a higher incidenceof unstable injuries in patients younger than 40 years; howeverage did not seem to be a factor influencing neurological recovery.Patients with stable injury who underwent surgery demonstrateda trend to less recovery compared to the non operated stablepatients. 4 patients made no neurological recovery but 14 (onethird) made a complete recovery (ASIA >95).

CONCLUSIONDue to small patient numbers, it was impossible to make statistically significant conclusions regarding the value of operativeintervention and timing of surgery. Patients with stable injurywho underwent surgery demonstrated a trend to less recoverycompared to the non operated stable patients. Irrespective oftreatment modality, there was a definite trend towards neurologicalrecovery. Continuing analysis of prospectively collected data in atertiary care spine trauma centre will be very useful in makingrecommendations in the management of these patients.

42




Free PaperSession 3

FUSIONFriday 19 April | 3.30pm - 4.30pm



24

43

3.30pm | 3.1

ACTIFUSE IS COMPARABLE TO INFUSE IN

ACHIEVING FUSION

*Licina P, 1, 2 Johnston MM,1, 2 Ewing L, 2 Pearcy MJ 2

1. Brisbane Private Research Group, Spring Hill, QLD Australia


University of Technology, QLD Australia

INTRODUCTION

There are an increasing number of alternatives to the use of

autogenous bone graft in spine surgery. BMP-2 (Infuse) has

demonstrated a high fusion rate but there are potential concerns

with associated complications including uncontrolled bone

formation, cyst formation and nerve irritation. Actifuse, a silicated

calcium phosphate with reported osteostimulatory properties,

may offer an alternative with a more favourable safety profile.

Additionally, the cost of Actifuse is less than half that of Infuse

and Mastergraft for a single level fusion.

METHODS

This prospective randomized controlled trial included patients

undergoing one and two level posterolateral instrumented fusion

for the treatment of degenerative lumbar disc disease. Blinded

radiological assessment was undertaken at twelve months using

thin slice CT and at six weeks, three months, six months, and 24

months using dynamic radiographs. The primary endpoint, fusion,

was determined by presence of bridging trabecular bone on CT.

Secondary endpoint measures were mobility on dynamic radi-

ographs, pain score (VAS), disability status (ODI), quality of life

(SF36) and neurological status. The Student t-test was used to

determine statistical significance.

RESULTS

Seventeen trial patients were blinded to surgical treatment of

Infuse (patients = 9, levels = 9) or Actifuse (patients = 8, levels =10).

One patient treated with Infuse withdrew from the study prior to

the 3 month postoperative review (due to unwillingness to par-

ticipate in the follow-up process), leaving 8 patients in each group.

Presence of posterolateral bridging of trabecular bone on CT

scan and absence of mobility on dynamic radiographs was seen

in all patients in the Actifuse group, and all but one patient in the

Infuse group. Mean clinical outcome measures (ODI, VAS, SF36)

of treated patients demonstrated comparable postoperative

improvement at 12 and 24 months. While most of the post-

operative measures showed statistically significant improvement

when compared with preoperative scores, there was no

statistically significant difference between the Infuse and Actifuse

groups (although the relevance of this is limited considering the

small sample size). There were no complications attributable to

graft material in either group.

CONCLUSION

This study has shown that results were similar for patients

treated with either Actifuse or Infuse, and hence, Actifuse may

be a viable alternative to Infuse for achieving posterolateral

fusion in degenerative lumbar conditions.

3.38pm | 3.2

BIOLOGICAL PERFORMANCE OF A

POLYCAPROLACTONE-BASED SCAFFOLD PLUS

RECOMBINANT HUMAN MORPHOGENETIC

PROTEIN-2 (rhBMP-2) IN AN OVINE THORACIC

INTERBODY FUSION MODEL

*Yong MR, 1, 2 Woodruff MA, 2 Askin GN, 1, 2 Labrom RD, 1, 2

Hutmacher DW, 2 Adam CJ 1, 2

1. QUT / Mater Paediatric Spine Research Group, Queensland

University of Technology, Mater Misericordiae Health Services,




INTRODUCTION

We develop a sheep thoracic spine interbody fusion model to

study the suitability of polycaprolactone-based scaffold and

recombinant human bone morphogenetic protein-2 (rhBMP-2)

as a bone graft substitute within the thoracic spine. The surgical

approach is a mini- open thoracotomy with relevance to

minimally invasive deformity correction surgery for adolescent

idiopathic scoliosis. To date there are no studies examining the

use of this biodegradable implant in combination with biologics

in a sheep thoracic spine model.

METHODS

In the present study, six sheep underwent a 3-level (T6/7, T8/9

and T10/11) discectomy with randomly allocated implantation of

a different graft substitute at each of the three levels;

44



FREE PAPER SESSION 3 | Fusion • Chair Claire Jones • 3.30pm - 4.30pm

(i) calcium phosphate (CaP) coated polycaprolactone based

scaffold plus 0.54µg rhBMP-2,

(ii) CaP coated PCL- based scaffold alone or

(iii) autograft (mulched rib head). Fusion was assessed at six

months post-surgery.

RESULTS

Computed Tomographic scanning demonstrated higher fusion

grades in the rhBMP-2 plus PCL- based scaffold group in

comparison to either PCL-based scaffold alone or autograft.

These results were supported by histological evaluations of the

respective groups. Biomechanical testing revealed significantly

higher stiffness for the rhBMP-2 plus PCL- based scaffold group

in all loading directions in comparison to the other two groups.

CONCLUSIONS

The results of this study demonstrate that rhBMP-2 plus

PCL- based scaffold is a viable bone graft substitute, providing an

optimal environment for thoracic interbody spinal fusion in a

large animal model.

3.46pm | 3.3

BIOMECHANICAL CHARACTERISTICS

OF AN INTEGRATED CERVICAL INTERBODY

FUSION DEVICE

*Voronov LI, 1, 2 Patwardhan AG, 1, 2 Havey RM, 1, 2 Vastardis G, 1, 2

Carandang G, 2 Potluri T, 2 Zelenakova J, 2 Abjornson C 3

1. Loyola University Chicago, Chicago, IL, USA

2. Edward Hines Jr. VA Hospital, Hines, IL, USA

3. Hospital for Special Surgery, New York, NY, USA

INTRODUCTION

Anterior cervical plating in conjunction with an interbody

cage/spacer provides enhanced stability and increased fusion

rates compared to interbody cage/spacer alone. Integrated

interbody cervical spine fusion implants combine the functionality

of an interbody spacer with the mechanical benefits of an anterior

cervical plate, while theoretically minimizing soft tissue irritation,

the risk of adjacent level ossification, and dysphagia due to their

no-profile design. This biomechanical study evaluated the stability

afforded by a lag-design integrated interbody fusion device with

screws (STALIF C®, Centinel Spine, West Chester, PA) to the

standard construct of an anterior plate and PEEK® cage in a

2-level construct. We hypothesized that the integrated construct

will have comparable biomechanical stability to the traditional

plating with spacers in a two-level fusion construct.

METHODS

Six fresh frozen human cadaveric cervical spine specimens

(C3-C7) were used. The angular motion of the C3 to C6

vertebrae relative to C7 was measured using an optoelectronic

motion measurement system. A six-component load cell was

placed under the specimen to measure the applied compressive

preload and moments. Fluoroscopic imaging was used to

document implant position. The follower load technique was

used to apply compressive preloads during flexion and extension.

Each specimen was tested in flexion-extension lateral bending

and axial rotation to ±1.5Nm. Experimental protocol included:

1. Intact

2. C5-C6 STALIF C®

3. C4-C5 STALIF C® (two-level construct)

4. Plated ACDF with PEEK spacers at C4-C5 and C5-C6

5. PEEK spacers alone at C4-C5 and C5-C6.

RESULTS

Single level ACDF with an integrated interbody cage at C5-C6

significantly reduced motion compared to intact. The average

ROM values decreased from 12.9±4.1 intact to 2.4±0.7 deg

(flexion-extension), 9.8±3.6 to 1.5±0.9 deg (lateral bending),

10.0±4.3 to 3.5±2.2 deg (axial rotation) (P<0.05 for all). When

comparing two-level (C4-C6) fusion using integrated interbody

cages to two-level plated construct using PEEK cages, the following

motions were noted across C4 to C6: 4.2±1.7 for integrated

cages vs. 2.1±0.9 degrees for plated construct in flexion-extension,

3.5±1.5 for integrated cages vs. 2.0±1.0 degrees for plated con-

struct in lateral bending, 6.7±3.6 for integrated cages vs. 4.1±2.2

degrees for plated construct in axial rotation (P<0.05 for all).

CONCLUSIONS

Single level ACDF using an integrated cage significantly reduced

motion compared to intact. When comparing the two, 2–level

constructs (integrated fusion vs. plate & spacers), the average

difference in motion was 2 degrees for all modes. This supports

the hypothesis that the effectiveness of the integrated interbody

fusion device would be biomechanically comparable to the

traditional spacer-anterior plate in a 2-level fusion construct.

45




3.54pm | 3.4

MAINTENANCE OF SEGMENTAL LORDOSIS

AND DISC HEIGHT IN STANDALONE AND

INSTRUMENTED EXTREME LATERAL INTERBODY

FUSION (XLIF)

*Gregory M Malham,1 Ngaire J Ellis,2 Rhiannon M Parker,2

Carl M. Blecher, 3 Rohan White, 3 Kevin A. Seex, 4 Ben Goss 5

1. Neuroscience Institute, Epworth Hospital, Melbourne, VIC, Australia

2. Greg Malham Neurosurgeon, Melbourne, VIC, Australia

3. Radiology Department, Epworth Hospital, Melbourne, VIC, Australia

4. Department of Neurosurgery, Macquarie University, Sydney,

NSW, Australia

5. NuVasive Australia / New Zealand, Melbourne, VIC, Australia

INTRODUCTION

Extreme lateral interbody fusion (XLIF) is gaining popularity as

a less invasive approach for anterior lumbar interbody fusion.

There is a paucity of information on the magnitude and

maintenance of lumbar lordosis and disc height correction when

comparing standalone XLIF to XLIF with supplemental posterior

instrumentation. The aim of this study was to assess whether

standalone XLIF maintained lordosis and disc height compared

with instrumented XLIF.

METHODS

Prospective data for 40 consecutive patients treated with XLIF

by a single surgeon was retrospectively reviewed. Standalone

XLIF and XLIF with supplemental bilateral pedicle screw fixation

cases were assessed. Assignment to each group was done by an

algorithm that takes into account bone density, facet arthropathy,

coronal or sagittal deformity and the number of levels.

Preoperative, postoperative and last follow up (fusion) computed

tomography (CT) scans were measured for posterior disc height,

segmental and lumbar lordosis by two independent radiologists.

Clinical outcome measures included pain (VAS (back and leg)),

disability (ODI) and quality of life (SF-36 (PCS and MCS)).

Statistical analysis included paired t-tests.

RESULTS

Twenty-one patients had standalone XLIF and 19 had XLIF with

supplemental posterior instrumentation. Median follow up was

12 months (range 6 to 12). For the standalone XLIF, lumbar

segmental lordosis increased from 7.9° to 9.4° (P = 0.050),

lumbar lordosis increased from 48.8° to 55.5° (P = 0.033) and

disc height increased from 3.7 mm to 5.5 mm (P = 0.002)

preoperatively to fusion. For the instrumented XLIF, segmental

lordosis increased from 7.6° to 10.5° (P = 0.012), lumbar lordosis

decreased from 51.1° to 45.8° (P = 0.256) and disc height

increased from 3.5 mm to 5.6 mm (P < 0.001) preoperatively

to fusion. For all patients mean VAS (back and/or leg) improved

46.5% and 39.2%, respectively, ODI had an improvement of

34.8% and PCS and MCS improved 39.8% and 4.9%, respectively.

All improvements were greater than the minimum clinically

important difference. 1 At 12 months 95% of the standalone and

80% of the instrumented XLIF were fused. 2

CONCLUSION

Patients receiving a standalone XLIF do not lose the gain in lumbar

segmental lordosis and the disc height restoration between the

preoperative and fusion time point when compared to patients

that receive XLIF with supplemental posterior fixation. It is highly

recommended that appropriate criteria are applied to discriminate

between patients assigned to each group.

REFERENCES

1. COPAY AG, GLASSMAN SD, SUBACH BR, BERVEN S,

SCHULER TC, CARREON LY

The Spine Jornal 2008; 8:968-974

2. WILLIAMS AL, GORNET MF, BURKUS JK

AJNR Am J Neuroradiol, 2005; 8:2057-2066

46




SocietySession

Friday 19 April | 4.30pm - 5.15pm



24

47

4.30pm

MSAC: GETTING GOVERNMENT APPROVAL

FOR NEW SPINAL TECHNOLOGY IN THE

LUCKY COUNTRY

Dr Graeme A Brazenor FRACS

Neuroscience Clinical Institute, Epworth Hospital, Melbourne, VIC

Australia

At the beginning of 2008 the Executive of the Spine Society

began to prepare, with the assistance of industry, an application

to the Australian Medical Services Advisory Committee (MSAC)

for cervical disc arthroplasty.

Previous application #1090 by industry in 2003 on lumbar and

cervical disc arthroplasty had failed to obtain permission for

cervical arthroplasty.

Spine Society’s application (#1145) was lodged with MSAC on

29th January 2010, and apart from 3 requests for extra data,

nothing was heard from the MSAC Secretariat until 15 months

later on 7th March 2011, when we received a 109 page

Evaluator’s Critique, with the request that we respond in 4 days.

From this point on there was continual gruelling correspondence

comprising email exchanges and 2 face-to-face meetings between

Spine Society and industry representatives on the one hand and

MSAC Secretariat members and contracted evaluators on the

other, over the 8.5 months until the final MSAC meeting to

consider the application on 29th November 2011.

There was then a further seven months of absolute radio silence

until the Minister announced her decision on 28th June 2012.

The total working + waiting time spent by Spine Society and

industry representatives on this project was 54 months, during

which period patients in most other western nations had access

to this technology.

4.45pm

WHY DO WE NEED A SPINE REGISTRY?

Dr Michael Johnson

Royal Children’s Hospital and Victorian Paediatric Orthopaedic

Centre, Melbourne, VIC Australia

5.00pm

A PRIMARY SPINAL TUMOUR DATABASE:

INTERNATIONAL COLLABORATION ON

SURGICAL OUTCOMES AND SURVIVAL

Associate Professor Richard Williams

AOSpine Reference Centre, Queensland University of Technology,


Primary spinal tumours are rare conditions. Malignant lesions

may be lethal, however, due to a relative paucity of large case

cohorts, surgical treatment principles are frequently derived on

a “case by case’ basis rather than adhering to a structure of

validated guidleines.

The Spinal Tumour subset of the recently formed Association for

Collaborative Spine Research (ACSR) together with the AOSpine

Tumour Knowledge Forum (AOSKF Tumour) allows for pooled

data collection from the world’s most widely recognised

musculoskeletal tumour centres in the hope of improving the

power of analysis of surgical treatment methods and leading to an

enhanced understanding of clinical outcomes and overall survival.

Having recently completed a retrospective data set of 1585

cases, the next phase is prospective collection of cases from all

contributing centres.

As the Australian representative collaborative centre, we would

welcome the contribution of primary spinal tumour case data

from any and all members of the Spine Society of Australasia,

regardless of how infrequently these lesions are seen and treated.

Subject to patient approval, our staff would be pleased to

complete the required data fields once alerted to the case by

the treating surgeon via a central email address

[email protected]

48



SOCIETY SESSION • Chair Peter Wilde • 4.30pm - 5.15pm

Free PaperSession 4

CLINICALSaturday 20 April | 8.30am - 10.00am



24

49

8.30am | 4.1

BONE SCANS ARE RELIABLE IN IDENTIFYING

LUMBAR DISC AND FACET PATHOLOGY

*Gregory M Malham,1 Ngaire J Ellis,2 Rhiannon M Parker,2

Kevin Seex,3 Ashish Diwan,4 John Ferguson,5 Neil Cleaver,6

Terrance Hillier,7 Leong Tan,8 Juan Uribe,9 Ben Goss 10

1. Neuroscience Institute, Epworth Hospital, Melbourne, VIC Australia

2. Greg Malham Neurosurgeon, Melbourne, VIC Australia

3. Department of Neurosurgery, Macquarie University, Sydney,

NSW Australia

4. Department of Orthopaedic Surgery, St George Hospital,


5. Auckland Bone and Joint Surgery, Auckland New Zealand

6. South Coast Spine, Gold Coast, QLD Australia

7. Albury Base Hospital, Albury, VIC Australia

8. Pindara Private Hospital, Gold Coast, QLD Australia

9. Department of Neurosurgery and Brain Repair, University of

South Florida, Tampa, FL USA

10. NuVasive Australia / New Zealand, Melbourne, VIC Australia

INTRODUCTION

Bone scans use radiolabelled bisphosphonates to identify areas

of abnormal osteogenesis. Technetium99m labelled methylene

diphosphonate (Tc99m-MDP) binds to hydroxyapatite at sites of

active osteoblast turnover. Bone scans use highly sensitive planar

imaging or SPECT, however specificity to spinal anatomy is low.

Advanced image fusion software enables bone scans to be

co-registered with high definition CT allowing anatomic localisation

of regions of increased Tc99m-MDP uptake. Pathology-specific

interventions such as epidural injections, facet joint blocks and

surgery can then be targeted more specifically. The aim of the

study was to evaluate the reliability of conventional bone scans

versus bone scans co-registered with CT and to assess inter-

observer reliability for identifying the anatomic location of

Tc99m-MDP uptake in lumbar disc, facet joint, or both.

METHODS

Seven spine surgeons interpreted 20 bone scans: 10 conventional

black and white tomograms (bone scans) and 10 colour graded

bone scans co-registered with CT (bone-CT). Each surgeon was

asked to identify the location of any clinically relevant uptake in

the disc, facet joint, or both between L1 and S1. Reliability was

evaluated using the free marginal kappa statistic and the level of

agreement was assessed using the Landis and Koch interpretation.

A kappa of ≥ 0.81 represents almost perfect agreement, 0.61- 0.80 represents substantial agreement, 0.41-0.60 represents

moderate agreement, 0.21- 0.40 represents fair agreement,

0.01- 0.20 represents slight agreement and values ≤ 0 representpoor agreement.

RESULTS

Overall Agreement Kappa

Bone Scans Any clinically79% 0.59relevant uptake

Bone-CT ScansAny clinically

86% 0.72relevant uptake

Bone Scans Uptake in disc 86% 0.72

Bone-CT Scans Uptake in disc 90% 0.81

Bone Scans Uptake in facet 80% 0.60

Bone-CT Scans Uptake in facet 91% 0.81

CONCLUSION

The interpretation of bone scans is reasonably reliable. For the

identification of disc pathology it is reliable to use either

conventional or bone scans co-registered with CT; however for

the facet joint bone scans co-registered with CT are more reliable.

8.38am | 4.2

CO-REGISTRATION OF ISOTOPE BONE SCAN

WITH CT AND MR IMAGES IN THE INVESTIGATION

OF SPINAL PATHOLOGY

*Graeme A Brazenor FRACS,1 Gregory M Malham FRACS,1

Zita E Ballok FRACP 2

1. Neuroscience Clinical Institute, Epworth Hospital,

Melbourne, VIC Australia

2. Nuclear Medicine Department, Primary Healthcare Imaging,

Epworth Hospital, Melbourne, VIC Australia

Image fusion software enables images from Technetium99m-

methylene diphosphonate (Tc99m- MDP) bone scan to be

co-registered with CT or MR images, allowing greater anatomical

discrimination in the co-registered images. 4-6

50

SATURDAY 20 APRIL 2013The Spine Society of Australia 24th Annual Scientific Meeting 2013


FREE PAPER SESSION 4 | Clinical • Chair Richard Williams • 8.30am - 10.00am

Our study aimed to investigate the role of bone scan images co-

registered with CT or MR in the investigation of patients presenting

to a spine surgeon with axial spinal pain, limb pain, or both.

139 consecutive patients presenting to a neurosurgical spinal

practice with axial spinal pain and/or limb pain were interviewed

and examined, and thereafter investigated with one or more of:

CT scan, MR scan, and dynamic plain films. At this point diagnosis

was declared with respect to Pathology type and Anatomical site,

and Treatment Intention was recorded.

Each patient’s Tc99m- MDP. bone scan images co-registered with

either CT or MR images were then studied, after which diagnosis

was re-declared with respect to Pathology type and Anatomical

site, and Treatment Intention was restated. Data was then

analysed to determine whether addition of the co-registered

isotope bone scan images had resulted in any change in diagnosis

with respect to Pathology type and/or Anatomical site, or

Treatment Intention.

The most important change in diagnosis after addition of the

isotope scan was in Pathology type, in 14 of the 139 patients

(10%). Anatomical site was changed markedly (without overlap

of the pre-isotope and post-isotope fields) in 7/139 patients

(5%); and changed with overlap in 14/139 (10%). The Treatment

Intention was changed markedly in 5/139 (3.6%), and in a minor

way in 12/139 (8.6%).

In particular in the two groups where there was:

1. no obvious pathology after full pre-isotope investigation, or

2. a spinal fusion under suspicion,

addition of the isotope bone scan information led to major

change in the Pathology and / or Anatomical localization in 18%

and 19% of patients respectively.

In the investigation of patients presenting with limb ± axial spinal

pain in a neurosurgical practice, the addition of Technetium99m-

methylene diphosphonate bone scan with images co-registered

with CT or MR images offers significant diagnostic assistance,

particularly in the difficult diagnostic groups where a spinal fusion

may be the suspected pain generator, or when no pain generator

can otherwise be found.

Key words:

Bone scan, CT, diagnosis, MR, pathology, treatment, spine.

8.46am | 4.3

ESTABLISHMENT OF A NOVEL IN VIVO MOUSE

MODEL OF SPINAL CANCER CAUSING EVOLVING

PARAPLEGIA

*Gerald MY Quan, Augusto Gonzalvo, Sathana Dushyanthen,

Effie Mouhtouris, Davina AF Cossigny

Spinal Biology Research Laboratory, Department of Spinal Surgery,

University of Melbourne Department of Surgery, Austin Health,

Melbourne, VIC Australia

INTRODUCTION

Patients with advanced cancer will more often than not develop

metastases to the spine, which if untreated causes intractable

pain and paralysis. Breast cancer in women and prostate cancer

in men are the most common primary cancer sources. Animal

models of spinal cancer are currently lacking but desperately

needed in order to improve understanding of the pathobiology

behind this devastating condition and to test adjuvant therapies.

For this reason, the aim of this study was to establish a

reproducible, clinically relevant small animal model of spinal

cancer that mimics the human condition.

METHODS

An orthotopic percutaneous injection of 2 x 105 human breast

(MDA-MB-231) or human prostate (PC-3) cancer cells suspended

in 5μL Phosphate Buffered Solution was administered into theupper lumbar spine of anaesthetized female and male nude mice

respectively (n=6). Animals were monitored twice daily for

general welfare, gait asymmetry or disturbance, and hindlimb

weakness. Plain radiographs and micro-CT imaging of each

mouse were performed at time of sacrifice. The thoracolumbar

spine junction was harvested en bloc, decalcified, processed,

embedded in paraffin wax and sectioned for histological analysis.

All procedures were approved by the Austin Health Animal

Ethics Committee (A2012-04395) and in accordance with

University of Melbourne guidelines.

RESULTS

All mice recovered fully from the inoculation procedure and

displayed normal gait and behaviour patterns for at least 3

weeks post-inoculation. Subsequently, between 3 to 5 weeks

post-inoculation, each mouse developed evolving paralysis in

their hindlimbs over 48 to 72 hours. All followed the same

pattern of decline following onset of neurological dysfunction;

51




from gait asymmetry and unilateral hindlimb weakness, to

complete unilateral hindlimb paralysis and finally to complete

bilateral hindlimb paralysis. Plain radiographs and micro-CT

scanning confirmed local tumour growth and destruction of the

spine of all six mice. Histological analysis confirmed cancer

growth within the vertebral body and spinal cord compression.

CONCLUSIONS

A novel in vivo mouse model of human spinal cancer has been

successfully established forming cancers that grow within the

spine and cause epidural spinal cord compression, resulting in a

reproducible and evolving neurological deficit and paralysis that

closely resembles the human condition. This enables us to

investigate the molecular mechanisms of cancer growth in the

spine and has the potential to provide a suitable platform to

trial novel therapeutics.

9.15am | 4.4

WHAT IS THE MOST CONSISTENT MEASURE OF

THORACOLUMBAR SPINAL SAGITTAL BALANCE?

AN ANALYSIS OF HEALTHY VOLUNTEERS

AGED 20-45

*Wilson PJ,1 Saravanja DD,2, 4 Sergides IG,3, 4 White GJ,4 Sears WR 1, 4

1. Neurosurgery, Australian School of Advanced Medicine,

Macquarie University Hospital, Sydney, NSW Australia

2. Orthopaedics, Australian School of Advanced Medicine,


3. Neurosurgery, Royal North Shore Hospital, Sydney, NSW Australia

4. Research Department, Wentworth Spine Clinic, Sydney, NSW

Australia

INTRODUCTION

Thoracolumbar spinal sagittal balance has attracted substantial

research in recent years, with the majority of literature based on

the Pelvic Incidence technique, described by Legaye and Duval-

Beaupere. 1 The Pelvic Radius technique, described by Jackson, 2

may be a simpler alternative that has received less attention.

The aims of this study were to compare both the consistency

of measurement and ease of use of these two techniques (Pelvic

Incidence and Pelvic Radius) in the assessment of thoracolumbar

sagittal balance.

METHODS

A normative database of thoracolumbar sagittal balance

parameters was created for young, asymptomatic volunteers

using EOS digital imaging (Biospace, Paris, France). Volunteers

aged 20-45 with no significant history of back or leg pain, nor

previous spinal surgery, were studied. Imaging of their whole

spine and lower limbs was conducted in a neutral standing

position. Images were then reviewed using Keops software

(SMAIO, Lyon, France) with calculation of previously described

parameters of pelvic incidence (PI – the angle formed between

the pelvic tilt [PT] and a line perpendicular to the sacral superior

endplate) 1 and pelvic morphology 2 (PRT12 - the angle formed

between the pelvic radius [PR] and the T12 inferior endplate).

Uni-variate correlations between variables were assessed using

linear regression. Significance was set at p<0.05.

RESULTS

Forty-nine volunteers were assessed. Key measured variables are

presented in Table 1.

Measured L1-S1 PI minus L1-S1variables PI lordosis lordosis PRT12

Mean 49.23 53.62 -8.06 92.99

SD 9.54 11.15 8.20 8.00

Min 29.55 27.21 -23.55 78.39

Max 82.19 85.54 7.07 107.42

Normality 0.151 0.590 0.187 0.078

Table 1. Key measured variables of thoracolumbar spinal sagittal

balance (degrees, PI = pelvic incidence, PR = pelvic radius, normality

= p value from Shapiro-Wilk test)

Strong correlations were found between PRT12 and pelvic angle

(PA) (r = 0.64, p < 0.0001), pelvic tilt (PT) and pelvic incidence

(PI) (r = 0.619, p < 0.0001), and between T4-T12 kyphosis and

L1-S1 lordosis (r = -0.493, p = 0.00037). No correlation was

found between PI and PRT12 (r = -0.177, p = 0.223).

CONCLUSION

The current study confirms the PRT12 to be a simple and

consistent, single measure of thoracolumbar spinal sagittal

balance, incorporating both pelvic morphology and lumbar

lordosis. In young, asymptomatic individuals, it approximates a

right angle (90 degrees). The PRT12 may provide a simpler

52




alternative for assessment of lumbo-pelvic alignment than pelvic

incidence. The latter may be more difficult to measure, requires

an additional measurement of the L1-S1 (lumbar) lordosis and

displayed a slightly larger standard deviation.

REFERENCES

1. LEGAYE J, DUVAL-BEAUPÈRE G, HECQUET J, MARTY C.

Pelvic incidence: a fundamental pelvic parameter for three

dimensional regulation of spinal sagittal curves. Eur Spine J.

1998;7(2):99–103.

2. JACKSON RP, HALES C.

Congruent spinopelvic alignment on standing lateral

radiographs of adult volunteers. Spine. 2000 Nov

1;25(21):2808–15.

9.23am | 4.5

RELATIONSHIP BETWEEN DEPRESSION AND

ACUTE LOW BACK PAIN AT FIRST MEDICAL

CONSULTATION, THREE, AND SIX WEEKS OF

PRIMARY CARE

*Melloh M,1 Käser A,2 Zweig T,3 Elfering A 2

1. Western Australian Institute for Medical Research (WAIMR),

University of Western Australia, Nedlands, WA Australia

2. Department of Work and Organizational Psychology, Institute of

Psychology, University of Berne, Berne, Switzerland

3. Department of Spinal Surgery, Discipline of Orthopaedics and

Trauma, School of Medicine, University of Adelaide, SA Australia

INTRODUCTION

Depression and low back pain (LBP) are among the most

common diseases that health practitioners encounter today.

They are related to each other; however, their relationship has

not yet been fully explored. The purpose of this study was to

model the longitudinal cause-effect relationship of depression

and LBP in patients presenting with acute LBP. We hypothesized

that depression and LBP are risk factors across time for each

other in the mid-term (six weeks) and even in the short-term

(three weeks).

METHODS

In a prospective inception cohort study, 221 primary care patients

with acute LBP were assessed at the time of initial consultation

and then followed up at three and six weeks. Key measures were

depression (modified Zung Self-Rating Depression Scale) and

pain (Short-Form McGill Pain Questionnaire). The relationship

between depression and LBP was examined by means of

cross-lagged models. A time lag of three weeks was chosen.

Age, gender and body mass index were introduced into the

models as control variables.

RESULTS

When only cross-lagged effects of six weeks were tested, a

reciprocal positive relationship between depression and LBP was

shown in a cross-lagged model (β = 0.15 and 0.17, p < .01).When lagged reciprocal paths at three- and six-week follow-up

were tested depression at the time of consultation predicted

higher LBP severity after three weeks (β = 0.23, p < .01). LBPafter three weeks had in turn a positive cross-lagged effect on

depression after six weeks (β = 0.27, p < .001). The severity ofacute LBP at initial consultation did not show any influence on

depression after three weeks.

CONCLUSIONS

Reciprocal effects of depression and LBP seem to depend on time

under medical treatment. Our findings suggest that depression at

the initial stage of LBP is involved in the maintenance of LBP.

LBP, in turn, might influence cognitions and foster the development

of depression. As a result, a vicious circle of depression and LBP

might develop. Pain medication at the beginning of the treatment

might prevent this process. Therefore, health practitioners

should screen for and treat depression at the first consultation

to prevent the development of persistent LBP.

REFERENCES

1. KROENKE K, WU J, BAIR MJ, KREBS EE, DAMUSH TM, TU W.

Reciprocal relationship between pain and depression: a

12-month longitudinal analysis in primary care. J Pain. 2011,

12:964-73.

2. HURWITZ EL, MORGENSTERN H, YU F.

Cross-sectional and longitudinal associations of low-back pain

and related disability with psychological distress among patients

enrolled in the UCLA Low-Back Pain Study. J Clin Epidemiol.

2003, 56:463-471.

53




9.31am | 4.6

BRIDGING THE GAP BETWEEN TREATMENT

EFFECTIVENESS AND PATIENT OUTCOMES

*Kahler RJ, Morrison EM, Walker DG, Bryant MJ, Coyne TJ,

Tomlinson FH

Newro Foundation, Auchenflower, QLD Australia

INTRODUCTION

Rates of surgery for degenerative cervical spine and degenerative

lumbar spine conditions are increasing by just over 9% pa over

the past 10years. However, the short and long term benefit

remains largely unquantified. There is increasing requirement to

provide evidence of the benefits of surgical intervention to

patients, institutions, insurance companies and other governing

bodies. A prospective online survey distribution and completion

Spinal Surgical Outcome Survey registry (SOS) was developed

as a quality improvement initiative, providing the platform to

collect patient related outcomes following surgery for

degenerative spinal disease. The purpose is to analyse prospective

data collected pre-operatively, 6 week, 6 month, 1 year and 2

years post-operatively.

METHODS

Patients undergoing elective surgery for degenerative cervical spine

and degenerative lumbar spine conditions were prospectively

registered in SOS. Patient’s received links to patient related

outcomes surveys via automated emails pre-operatively, 6 week,

6 months and 1 Year post-operatively. Surveys were competed

online and data exported to the SOS data server on survey

completion. A paper-based method of survey completion was

available where internet access was unavailable. Corresponding

clinical assessment and surgical information was collected from

the treating surgeon. Outcomes were measured using the

validated disability indices tools, Roland Morris(RM), Oswestry

Disability Index(ODI), Neck Disability Index(NDI), SF-12 Mental

Component Score (MCS)/Physical Component Score (PCS),

Visual Analog Scales (VAS) to determine pain, numbness and

weakness, and patient overall satisfaction.

RESULTS

A total of 314 patients have been recruited by a single surgeon.

Out of the patients having completed 12 months post-operative

follow up, 61 had Lumbar spine surgery and 16 (6 Male and 10

Female) had cervical spine surgery. All outcome measures were

analysed against the pre-operative assessment.

Table 1: Outcome Measures at 12 Months

Lumbar CervicalMean Difference (CI) Mean Difference (CI)

SF-12® PCS -13.5 (-16.7 - -10.3)* -7.4 (-11.9 - -2.9)*

SF-12® MCS -6.2 (-9.2 - -3.2)* -6.5 (-11.3 - -1.6)**

NDI 18.4 (9.4 – 27.4)*

ODI 27.0 (22.1 – 31.7)*

RM 7.7 (6.3 – 9.2)*

*p<0.001 **p<0.05

CONCLUSIONS

SOS has proven to be effective in assessing the clinical outcomes

of patients undergoing surgery for degenerative conditions of

the spine. It has proven to be a cost-effective and efficient

assessment method providing evidence of quality improvement,

measuring quality of care and Outcome benchmarking. We

believe that SOS has significant potential to provide objective

evidence in analyzing the gap between patient reported

outcomes and perceived clinical effectiveness.

54




Symposium:Biology of SpinalCord Preservationand Restoration

Saturday 20 April | 10.30am - 12.30pm



24

55

10.30am

STUDIES IN TRANSPLANTATION THERAPIES

FOR SCI: COMBINATORIAL APPROACHES

USING PURIFIED MULTIPOTENT HMPCS

ISOLATED FROM SCI PATIENTS, ANTI-SCARRING

AGENTS, IPSCS AND A LOOK TO THE FUTURE

Associate Professor Stuart Hodgetts

Spinal Cord Repair Lab, School of Anatomy & Human Biology,

University of Western Australia, Perth, WA Australia

Over the last decade, our laboratory has focussed on the

potential of purified (Stro-1+) human mesenchymal precursor

cells (hMPCs) to repair the injured spinal cord after

transplantation into T cell deficient athymic RNU nude rats

following acute and chronic moderate contusive spinal cord

injury (SCI). Isolated from the bone marrow of SCI patients,

these hMPCs have been used in combinatorial approaches

and been shown to markedly improve morphological and

functional outcomes in our rat models. This occurs despite

the fact that the cells ultimately do not survive long term.

Combinatorial experiments with immunosuppression and the

use of anti-scarring agent, have repeatedly highlighted these

donor cells as promising candidates for SCI therapies.

Our laboratory is currently investigating the ability to prolong

donor hMPC survival post transplantation and further enhance

these outcomes, as well as exploring the use of inducible

pluripotent stem cell (iPSC) technology, nanotechnology

delivery and gene therapy techniques as preclinical strategies

designed to promote regeneration after SCI.

10.48am

CELL THERAPIES: STEM CELLS, SCHWANN

CELLS, AND OLFACTORY ENSHEATHING CELLS

Associate Professor Brian Kwon

Department of Orthopaedics, University of British Columbia and

Spinal Surgery, Vancouver General Hospital, British Colombia, Canada

Cellular transplantation treatments have been tested

extensively for the treatment of spinal cord injuries (SCI) in

the laboratory setting, and more recently, in human patients.

Various cell types have been investigated, based on the

following properties:

1. the potential to form myelin,

2. the potential to promote and guide axonal growth

3. the potential to bridge the site of injury where cystic

cavitation has occurred

4. the potential to secrete trophic factors which may have

neuroprotective effects and/or promote plasticity in the

spared spinal cord.

Hence, the beneficial effects of these cellular therapies are

multi-factorial and often difficult to attribute to one single

mechanism. The therapeutic goals of promoting remyelination,

facilitating axonal sprouting, bridging of the lesion, and secretion

of trophic factors appears to be met by a number of cellular

substrates. These encouraging findings have prompted clinial

trials of a number of therapies. Such clinical trials should not

be confused with unregulated “experimental treatments” that

patients receive in the plethora of ‘stem cell clinics’ that have

emerged in the last decade. While generating much hope

amongst patients, these unregulated “stem cell” treatments

have not demonstrably improved neurologic outcome after

SCI and clinicians are advised to NOT advocate for such

experimental treatments for their patients.

56



SYMPOSIUM: Biology of spinal cord preservation & restoration • Chair Peter Wilde • 10.30am - 12.30pm

11.06am

MOVING IPS CELL TECHNOLOGY CLOSER TO

THE CLINIC: MAKING HLA MATCHED CLINICAL

GRADE IPS CELLS FROM HUMAN CORD BLOOD

USING MODIFIED RNA TRANSFECTION

METHODS IN XENO FREE CELL CULTURE

CONDITIONS AND TO DIFFERENTIATE TO

SPHERICAL NEURONAL MASSES

Dr Michael Edel

Department of Physiological Science, Molecular Genetics Research

Group, Faculty of Medicine, University of Barcelona, Spain

The Barcelona-based Pluripotency Laboratory is advancing

induced pluripotent stem cell (iPS cell) technology closer to

ground state pluripotency for clinical applications and is part

of the University of Barcelona Faculty of Medicine. We aim

to understand the role of cell cycle and epigenetic genes in

attaining ground state pluripotency. Furthermore we aim to

define efficient differentiation protocols of iPS towards

progenitor stem cells of various tissues. The laboratory

addresses a number of major bottlenecks in the field such

as the threat of genetic instability, immune response of iPS

derived cells and to define clinical cell culture conditions for

eventual cell replacement therapy for different types of human

disease. This talk will focus on developing the technology to

make high quality clinical grade iPS cells that are HLA matched

to the Spanish population. The talk will highlight the current

stage in differentiation of iPS cells towards cells to treat spinal

cord injury. For more information please see my laboratory

web page: www.pluripotencylaboratory.wordpress.com/

11.39am

NEUROPROTECTION OF THE INJURED

SPINAL CORD: UPDATE ON THE

TRANSLATIONAL PIPELINE

Professor Michael Fehlings

Krembil Neuroscience Center, Spinal Program at Toronto Western

Hospital and Neurosurgery Department at the University of Toronto,

Ontario, Canada

57




11.57am

IMMEDIATE COOLING AND EMERGENCY

DECOMPRESSION FOR TREATMENT OF SCI

*Peter E Batchelor, Nicole F Kerr, Amy M Gatt, Susan F Cox,

Ali Ghasem-Zadeh, Taryn E Wills, Peta Skeers, Tara K Sidon,

David W Howells

FNI and University of Melbourne, Austin Health, VIC Australia

INTRODUCTION

Human SCI is usually accompanied by persistent cord

compression. Experimentally cord compression results in rapid

neurological decline over hours. Undertaking decompression

in humans within hours is impractical and there is therefore

an important need for a therapy to prevent the neurological

deterioration of patients prior to decompressive surgery.

The aim of this study was to determine if hypothermia limits

neurological decline following compressive SCI and reduces

raised local intracanal pressure.

METHODS

Rats were subject to a moderate thoracic SCI and spacers

inserted to compress the spinal cord by 45%. Canal pressure

was monitored via a canulae within the spacer. Decompression

was performed 0, 2 or 8 hours post-injury. Hypothermia

(33oC) was commenced in half the animals 30mins post-injury

and maintained for 7.5 hours, with the other half remaining

normothermic. Motor recovery was assessed weekly and the

volume of tissue damage determined at 8 weeks.

RESULTS

Hypothermia significantly improved the behavioural and

histological outcome of animals undergoing 8 hours of

compressive injury (primary outcome measure). The

hypothermia treated group (n=16) regained weight-supported

locomotion (BBB score 9.5±0.9) while the normothermia

group (n=16) remained severely paraparetic (BBB score

5.3±0.6, P≤0.0005, E.S.=1.4). Hypothermia reduced mean

local intracanal pressure from over 30 mmHg to around 13

mmHg (n=9, p<0.001) and neurological recovery was closely

linked to the rise in local intracanal pressure.

CONCLUSION

Hypothermia significantly slows the rate of neurological

deterioration accompanying cord compression by reducing

local intracanal pressure and may be a useful bridging therapy

to prevent neurological decline prior to decompressive

surgery. Hypothermia is currently initiated by paramedics in

the field following cardiac arrest and head injury and may be

usefully employed following SCI to “medically decompress”

the spinal cord prior to definitive surgical decompression.

58




Free PaperSession 5

BIOMECHANICSSaturday 20 April | 1.30pm - 3.00pm



24

59

1.30pm | 5.1

BIOMECHANICAL COMPARISON OF ANTERIOR &

LATERAL PLATING AFTER INTERBODY FUSION

USING A NOVEL SYNTHETIC SPINE MODEL

* Jonathon R Ball,1 Matthew H Pelletier,2 Tian Wang,2

William R Walsh 2

1. Royal North Shore and North Shore Private Hospitals,

Sydney, NSW Australia

2. Surgical & Orthopaedic Research Laboratories, University of New

South Wales, Sydney, NSW Australia

INTRODUCTION

Lateral approaches for interbody fusion are increasing in popularity.

Supplementary fixation is recommended for additional stability.

This supplementation is often achieved through a posterior

approach, adding to surgical invasiveness, morbidity, expense

and time. The aim of this study was to assess the mechanical

performance of lateral plating following lateral interbody fusion

using a novel synthetic spine model.

METHODS

Three synthetic, bio-mimetic spine models of the L3/4 motion

segment (SawBones, Vashon, WA, USA) were tested in pure

moment bending using a validated testing rig. Moments were

applied to induce flexion-extension (FE), lateral bending (LB) and

axial rotation (AR). Motion segment kinematics were evaluated

using an optoelectronic motion system for calculation of range of

motion and neutral zone.

Each model was tested in the 4 following conditions:

1) intact spine,

2) lateral cage alone

3) lateral cage and plate

4) anterior cage and plate - results were analysed using

ANOVA with post-hoc Tukey’s HSD test.

RESULTS

The intact synthetic spine surrogates exhibited biomechanics

that were comparable to that of reported cadaveric values.

The range of motion for a lateral cage and plate construct was

not significantly different to the ‘gold standard’ anterior lumbar

interbody construct for flexion-extension (p=1.00), lateral bending

(p = 0.995) and axial rotation (p = 0.837). Compared to the

intact state, a lateral cage alone reduced range of motion for

lateral bending by 68% (p = 0.010), for flexion-extension by 51%

(p = 0.065) but did not seem to significantly affect axial rotation.

Range of Motion (degrees)

Axial Rotation Flexion Extension Lateral Bending

Intact

Lateral Cage

Lateral Cage and Plate

Anterior Cage and Plate

CONCLUSIONS

Lateral lumbar interbody fusion with lateral plating reduces range

of motion to a similar degree as anterior lumbar interbody fusion

with plating. The addition of lateral plating to lumbar interbody

fusion may avoid the need for a separate posterior approach for

supplementary fixation.

1.38pm | 5.2

THE EFFECT OF TESTING PROTOCOL ON

IMMATURE BOVINE THORACIC SPINE SEGMENT

STIFFNESS

*Sunni N, Askin GN, Labrom RD, Izatt MT, Pearcy MJ, Adam CJ

QUT / Mater Paediatric Spine Research Group, Queensland University

of Technology, Mater Health Services, Brisbane, QLD Australia

INTRODUCTION

In vitro spine biomechanical testing has been central to many

advances in understanding the physiology and pathology of the

human spine. Owing to the difficulty in obtaining sufficient numbers

of human samples to conduct these studies, animal spines have

been accepted as a substitute model. However, it is difficult to

compare results from different studies, as they use different

preparation, testing and data collection methods. The aim of this

study was to identify the effect of repeated cyclic loading on

bovine spine segment stiffness. It also aimed to quantify the effect

of multiple freeze-thaw sequences, as many tests would be

difficult to complete in a single session. 1 - 3

60



FREE PAPER SESSION 5 | Biomechanics • Chair Mark Pearcy • 1.30pm - 3.00pm

25

20

15

10

5

0

METHODS

Thoracic spines from 6-8 week old calves were used. Each spine

was dissected and divided into motion segments including levels

T4-T11 (n=28). These were divided into two equal groups. Each

segment was potted in polymethylemethacrylate. An Instron Biaxial

materials testing machine with custom jig was used for testing.

Segments were tested in flexion/extension, lateral bending and

axial rotation at 370C and 100% humidity, using moment control to

a maximum ±1.75 Nm with a loading rate of 0.3 Nm per second.

Group (A): 14 segments were tested with continuous repeated

cyclic loading for 500 cycles with data recorded at cycles 3, 5, 10,

25, 100, 200, 300, 400 and 500.

Group (B): 14 segments were tested with 10 load cycles after

each of 5 freeze thaw sequences. Data was collected from the

tenth load cycle after each sequence. Statistical analysis of the

data was performed using paired samples t-tests, ANOVA and

generalized estimating equations.

RESULTS

The data were confirmed as having a normal distribution.

1. There were significant reductions in mean stiffness in flexion

/ extension (-20%; P=0.001) and lateral bending (-17%;

P=0.009) over the 500 load cycles. However, there was no

statistically significant change in axial rotation (P=0.152)

2. There was no statistically significant difference between mean

stiffness over the five freeze-thaw sequences in flexion /

extension (P=0.879) and axial rotation (P=0.07). However,

there was a significant reduction in stiffness in lateral bending

(-26%; P=0.007)

CONCLUSION

Biomechanical testing of immature bovine spine motion segments

requires careful interpretation. The effect of the number of load

cycles as well as the number of freeze-thaw cycles on the stiffness

of the motion segments depends on the axis of main movement.

REFERENCES

1. HONGO M, GAY RE, HSU JT, et al.

Effect of multiple freeze-thaw cycles on intervertebral dynamic

motion characteristics in the porcine lumbar spine. J Biomech.

2008;41(4):916-20.

2. KETTLER A, LIAKOS L, HAEGELE B, WILKE HJ.

Are the spines of calf, pig and sheep suitable models for

pre-clinical implant tests? Eur Spine J. 2007;16(12):2186-92.

3. WILKE HJ, JUNGKUNZ B, WENGER K, CLAES LE.

Spinal segment range of motion as a function of in vitro test

conditions: effects of exposure period, accumulated cycles,

angular-deformation rate, and moisture condition. Anat Rec.

1998;251(1):15-9.

1.46pm | 5.3

EVALUATION OF SYNTHETIC FUNCTIONAL

SPINE UNIT: PURE MOMENT CYCLE TEST

*Wang T, Pelletier MH, Walsh WR

Surgical and Orthopaedic Research Laboratories, Prince of Wales

Clinical School and Graduate School of Biomedical Engineering,


INTRODUCTION

Laboratory tests of spinal biomechanics allow the evaluation

of hypotheses that are not possible in vivo, however these tests

have their limitations. Cadaveric tissues carry with them the

potential for disease transmission, and cost as well as availability,

variability and quality issues. Animal tissues may be used in place

of human cadaveric tissues; however they may not perfectly

simulate the human anatomy and biomechanics. Fresh tissues

also suffer from decay and fatigue over large number of repeated

tests. Therefore, a synthetic biomimetic spine model may be a

suitable replacement. The goal of current study is to evaluate the

3D biomechanical properties of a synthetic biomimetic spine

model.

METHODS

Three L3/4 synthetic spinal motion segments, recently

developed by SawBones (Vashon, WA, USA) were examined

using a validated pure moment testing system. Moments (±7.5Nm)

were applied in flexion-extension (FE), lateral bending (LB) and

axial rotation (AR) at 1Hz for total 10000 cycles in MTS Bionix.

Motion was assessed at 1, 125, 250, 500, 1000, 2500, 5000 and

10000 cycles. An additional test was performed 12 hours after

10000 cycles. A ±10Nm cycle was also performed to allow

provide comparison to the literature. A near infrared 3D motion

tracking system with retro-reflective markers (Osprey, Motion-

Analysis, Santa Rosa, CA) and post processing was performed with

an in-house written script MATLAB (MathWorks, Natick, MA).

61




Table 1: Comparison of the ranges of motion (ROM) of synthetic

model and human spine data from other studies. Number in

parentheses shows the standard deviation. Flexion-extension (FE),

lateral bending (LB) and axial rotation (AR).

CONCLUSION

Based on the biomechanical similarities, the synthetic spine tested

here provides a reasonable model to represent the human lumbar

spine. Small intra-specimen variability and lack of biohazard makes

this an attractive alternative for in vitro spine biomechanical

testing. Clearly, more testing is required in the future to evaluate

this synthetic model for more complex applications.

REFERENCES

1. PANJABI MM, OXLAND TR, YAMAMOTO I, CRISCO JJ

Mechanical behavior of the human lumbar and lumbosacral

spine as shown by three-dimensional load-displacement

curves. The Journal of bone and joint surgery American

volume. 1994;76(3):413-24.

2. YAMAMOTO I, PANJABI MM, CRISCO T, OXLAND T

Three-dimensional movements of the whole lumbar spine

and lumbosacral joint. Spine. 1989;14(11):1256-60

3. WHITE AA, PANJABI MM

Clinical Biomechanics of the Spine. 2nd ed. Philadelphia:

JB Lippincott, 1990.

2.15pm | 5.4

THE EFFECT OF THE INTERVERTEBRAL DISC

HYDRATION ON SPINAL BIOMECHANICS

*Wang T, Pelletier MH, Walsh WR

Surgical and Orthopaedic Research Laboratories, Prince of Wales

Clinical School and Graduate School of Biomedical Engineering,


INTRODUCTION

Water content is an important determinant of disc behaviour

and also relevant to the interverebral disc (IVD) degeneration.

The aim of this study was to assess the effect of suprahydrated

and dehydrated states on the range of motion (ROM) and

neutral zone (NZ) of the IVD.

METHODS

Functional spinal units (FSU) were prepared from fresh frozen

ovine lumbar spines within 3 month of death and randomly

assigned to two groups. Pure moment (7.5Nm) tests in axial

rotation (AR), flexion, extension (FE) and lateral bending (LB)

were performed with 3D motion capture. The supra hydrated

group was tested in air and submerged in a water bath 8 hours

under 0.08MPa pressure. The dehydrated group was tested in air

then placed in a 10x Phosphate Buffered Saline (PBS) bath for 8

hours under 0.08MPa pressure. The height changes of the IVDs

were recorded. Following soaking, both groups were tested again.

RESULTS

ROM increased by 8%, 5% and 5% respectively under AR, FE and

LB in the dehydrated group when compared testing in air. NZ

was increased by 70%, 17% and 18% respectively under AR, FE

62




RESULTS

Range of Motion (ROM) in all three planes increased logarithmically through cycle tests.

Values were within range of published human data.

7.5Nm 10Nm

ROM First Cycle 10K Cycle 12h after Panjabi 1 Yamamoto 2 Current study White & Cycle Test Panjabi 3

AR 3.7 (0.6) 4.3 (0.7) 4.2 (0.8) 3.4 4.5 5.9 (1.8) 5.2 (2.0)

FE 8.6 (1.9) 11.8 (2.3) 11.8 (2.4) 8.9 10.4 18.1 (4.9) 16.0 (7.0)

LB 9.1 (3.4) 11.3 (3.0) 11.0 (3.2) 10.2 10.8 14.3 (3.4) 16.0 (8.0)

and LB motion. In the supra hydrated group, ROM was decreased

17%, 5% and 5% respectively under AR, FE and LB. NZ decreased

50%, 18% and 14% respectively under AR, FE and LB.

After normalizion of data with standard air testing, results show

that the supra hydrated ROM was lower (p<0.05) than the

dehydrated for all motions. Supra hydrated groups showed a

lower (p<0.05) NZ when compared to the dehydrated group

for all but AR. When compared with the supra hydrated group,

in AR, ROM was 18% greater and NZ was increased 97%

following dehydration; in FE, ROM was increased 22% and NZ

was increased 46%; and in LB, ROM was increased 9% and NZ

was 19% greater in dehydrated group.

CONCLUSION

The biomechanics of spinal segments with supra hydrated and

dehydrated discs differ considerably. As this is a prominent

feature of degenerative disc disease (DDD), this alteration in

spinal motion is likely present patients suffering from DDD.

2.23pm | 5.5

MICROTENSILE PROPERTIES OF INDIVIDUAL

FIBRE BUNDLES IN HEALTHY AND DEGENERATE

HUMAN ANULUS FIBROSUS

*Costi JJ,1 Pham DT,1 Shapter JG 2

1. Medical Device Research Institute, School of Computer Science,

Engineering & Mathematics, Flinders University, SA Australia

2. School of Chemical & Physical Sciences, Flinders University, SA

Australia

INTRODUCTION

Intervertebral disc degeneration is a common condition that has

been shown to be linked to low-back pain, yet its aetiology is not

fully understood. Investigating the mechanics of the disc on a

micro-scale could help clarify its origins and allow us to develop

more effective methods of diagnosis and treatment.

A prominent feature of the disc is the anulus fibrosus, the fibrous,

multi-layered region that lies on the periphery. This study

investigated the Young's Modulus, E, of individual fibre bundles

extracted from healthy and degenerate anulus fibrosus.

METHODS

Seven healthy (Thompson grades 2-3) and seven degenerate

(Thompson grades 4-5) human intervertebral discs were

harvested from cadaveric lumbar spines and dissected

transversely. Individual fibre bundles, containing unidirectional fibres,

were extracted from the outer lamellae of four different

anatomical regions:

Posterolateral, Lateral, Anterolateral and Anterior

To improve gripping strength, fabric tabs were glued to either

end of each fibre bundle, perpendicular to the fibre direction.

Uniaxial tensile testing along the fibre bundle axis was conducted

using a CellScale BioTester (CellScale, Canada). A preload of

approx. 50 mN was applied for 10 mins, before the sample was

subjected to 10 dynamic cycles at a strain rate of 0.1% / s. The

mean maximum strain was 22%, which was found to lie within the

linear portion of the stress-strain curve. All tests were conducted

in a 0.15M PBS bath maintained at 37±1°C. The mean E was

calculated from the linear portion of the last 5 cycles of each test.

RESULTS

Early analysis indicates that the elastic properties of the fibre

bundles in the anulus fibrosus are consistent between the four

anatomical regions, and does not differ between healthy and

degenerate discs. Data analysis is still ongoing, and is expected to

be complete by April 2013.

CONCLUSION

Studies investigating higher structural levels (ie single1 and

multiple 2 anulus layers) have observed regional differences in

mechanical behaviour. Uniformity at the fibre bundle level

suggests that the arrangement and interconnection of these

bundles notably contribute to the overall mechanical behaviour

of the anulus fibrosus layers. Furthermore, the consistency

between healthy and degenerate specimens at the fibre bundle

level suggests that degeneration could originate at the lamella

level and above. This research forms part of a project exploring

the nano- and micro-mechanical properties of the human anulus

fibrosus.

REFERENCES

1. SKAGGS DL, et al.,

Spine 19(2): 1310-1319, 1994.

2. ACAROGLU ER, et al.

Spine 20(24): 2690-2701, 1995.

63




2.31pm | 5.6

DOES COMBINED COMPRESSION, FLEXION AND

AXIAL ROTATION PLACE THE DISC AT RISK OF

POSTEROLATERAL HERNIATION? MEASUREMENT

OF 3D LUMBAR INTERVERTEBRAL DISC INTERNAL

STRAINS DURING REPETITIVE LOADING

*Costi JJ,1 Heinze K,2 Lawless IM,1 Stanley RM,1 Freeman BJC 3

1. Medical Device Research Institute, School of Computer Science,

Engineering & Mathematics, Flinders University, SA Australia

2. Dept of Biomedical Engineering and Physics, Vrije University,

Amsterdam, The Netherlands

3. Adelaide Centre for Spinal Research, The University of Adelaide,

SA Australia

INTRODUCTION

Chronic low back pain (LBP) is a crippling and insidious drain on

one’s quality of life and is a significant burden to both the health

care system and the workforce. 1 The mechanisms of LBP are

largely poorly understood but it is well known that loss of

intervertebral disc (disc) height due to degeneration is a common

cause of chronic low back and referred pain. Gross disc injury

such as herniation can be caused cumulatively or by sudden

overload and is both a cause of acute LBP and an accelerant of

disc degeneration. 2, 3 This study analyses a direction and style

of motion hypothesised to place the disc at greatest risk of

posterolateral herniation.

METHODS

Ten human lumbar Functional Spinal Units (FSUs) had a grid of

tantalum wires inserted into the disc and were subjected to

20,000 cycles of repetitive loading in combined compression,

flexion and right axial rotation. Stereoradiographs were taken at

cyclic intervals (1, 500, 1,000, 5,000, 10,000, 15,000 and 20,000

cycles) from which 3D internal principal strains and maximum

shear strains (MSS) in the disc were calculated and partitioned

into nine disc anatomical regions. 4 After testing the discs were

sectioned and macroscopically assessed to correlate tissue

damage with regions of highest internal disc strain. An ANOVA

was used to examine the effects of cycle number and anatomical

region on MSS.

RESULTS

No visible evidence of disc herniation occurred after 20,000

cycles, however an annular tear was present in a number of

cases. There was a significant effect of both number of cycles and

disc region on maximum shear strain magnitude (p<0.001).

There was an increase in MSS with increasing cycle number in

the anterior, left lateral, left/right anterolateral, left posterolateral

regions and nucleus. An overall decrease in MSS was seen in the

right lateral and right posterolateral regions. The largest increases

were observed in the left anterolateral and left posterolateral

regions after 20,000 cycles.

CONCLUSION

An increase in MSS was observed across most regions in the

disc, especially in the left posterolateral region, suggesting internal

disc tissue disorganisation that may indicate a progression towards

annular tears and eventual herniation.

REFERENCES

1. AIHW. Cat. no. PHE 115, 2009.

2. ADAMS MA, HUTTON WC.

Spine 7:184-91, 1982.

3. ADAMS MA, HUTTON WC.

Spine 10:524-31, 1985.

4. COSTI JJ et al.

J. Biomech 40:2457–2466, 2007.

64




The Gettingof SurgicalWisdom

Saturday 20 April | 3.30pm - 4.30pm



24

65

3.30pm

TWO YOUNG LADIES

Dr Peter Woodland

Spinal Unit, Department of Orthopaedic Surgery, Royal Perth

Hospital, WA Australia

Two totally unexpected sentinel events involving young

patients at Royal Perth Hospital in 2004–2005, prompted

much soul-searching and an independent review of the entire

Western Australian Scoliosis–Deformity Service.

Subsequent focus was on the post-operative management of

scoliosis patients, in particular those having undergone single

stage thoracotomy/anterior release and then posterior

correction surgery.

The use of intra-pleural Ropivacaine local anaesthetic, in this

subgroup of patients, was also closely scrutinised.

The lead surgeons’ response to the events of this devastating

period is discussed, in the context of almost 700 paediatric

scoliosis–spinal deformity cases being carried out from 1993

to 2012 inclusive, by the Western Australian Service.

3.45pm

Dr Matthew Scott-Young

Gold Coast Spine, Pacific Private Clinic and Allamanda Private

Hospital, Southport, QLD

4.00pm

PLIF: Risky business or just another learning curve?

Dr William Sears

Australian School of Advanced Medicine, Macquarie University

Hospital and Research Department, Wentworth Spine Clinic,

Sydney, NSW Australia

4.15pm

Thoraco lumbar junction: Stop sign or proceed with caution?

Dr Peter Moloney

Spinal Surgery and Neurosurgery Private Practice,

Sydney, Bowral, Wollongong and Goulburn, NSW Australia

The Getting of Surgical Wisdom • Chair Ralph Stanford • 3.30pm - 4.30pm

66



Free PaperSession 6

LUMBARSunday 21 April | 8.30am - 10.00am



24

67

8.30am | 6.1

MICROSURGICAL DECOMPRESSION WITH COFLEX

INTERSPINOUS DYNAMIC STABILIZATION FOR

TREATING LUMBAR DEGENERATIVE STENOSIS

*Hossum El Noamany

Menoufiya University Hospital, Menoufiya, Egypt

INTRODUCTION

Degenerative lumbar canal stenosis is a disease affecting

population between 40 - 80 years of age and is treated by many

surgical modalities. Patients suffering from a single level

degenerative lumbar spinal stenosis are included in this prospective

cohort study. The purpose of this study is to determine efficacy

and safety and to analyze the clinical and radiological results of

using Coflex device after microsurgical decompression of a single

level degenerative lumbar spinal stenosis.

METHODS

Twelve patients with lumbar spinal stenosis who treated by micro-

surgical decompression and Coflex stabilization were reported.

Coflex stabilization was used after decompression of lumbar

canal to treat degenerative segmental stenosis. 10-point Visual

Analogue Scale (VAS) was used to evaluate leg pain and back

pain at one month, 6 months, and one year post procedure. The

neurogenic claudication distance was also calculated. The median

follow- up period was 42 months. Radiographic data was collected

and implant position and spinal segment motion was evaluated.

RESULTS

Back pain was significantly improved in 83.3% of patients

(P<0.05), while radiculopathic pain was significantly improved in91.6% of patients (P<0.05). Also significant improvement in walkingdistance is achieved in 91.6% of the patients (P<0.05). No expulsions or implant migration in postoperative follow-up

occurred. Radiographic analysis revealed a significant decrease in

spinal segment motion postoperatively during follow-up period.

CONCLUSIONS

Coflex implantation is safe and effective in treating degenerative

lumbar spinal stenosis. It is rapid minimally invasive technique

with no reported serious complications. It also, demonstrates

excellent results along the whole time of follow-up for

improvement of back pain, neurogenic claudication and patient’s

postoperative satisfaction.

8.38am | 6.2

INFLUENCE OF PREVIOUS CONSERVATVE

TREATMENT INTERVAL ON OUTCOMES

FOLLOWING DECOMPRESSIVE SURGERY FOR

LUMBAR DISC HERNIATION

*T Zweig,1, 2 YH Yau,1 BJC Freeman,1 M Melloh,2 E Aghayev,2

C Röder,2 on behalf of the EuroSpine

1. Department of Spinal Surgery, Discipline of Orthopaedics and

Trauma, School of Medicine, University of Adelaide, SA Australia

2. IEFM at MEM Research Centre, University of Bern, Switzerland

INTRODUCTION

Symptomatic lumbar disc herniation is a well-accepted surgical

indication for decompression, yet the optimal timing for such

surgery remains unclear, given the likelihood for spontaneous

symptomatic improvement. We hypothesized that there is a

difference in the outcomes observed following decompression

surgery dependent on the duration of previous conservative

treatment (none, <3 months, 3-6 months, 6-12 months, >12

months).

MATERIAL & METHODS

Spine Tango, the nonprofit International Spine Registry of

EuroSpine currently contains more than 40,000 spinal surgical

procedures; at point of time 9,000 cases are fully documented

with pre- and postoperative patient- and physician based

assessment. This study examined 2,176 cases of single level

lumbar disc herniation that underwent surgical intervention.

Pre- and post-operative patient-based assessment of leg and

back pain indicated on a Visual Analogue Scale (VAS) from 0 to

10 and the back specific Core Outcome Measures Index (COMI)

were recorded. Additional physician-based documentation

including surgical treatment (specification of main pathology,

detailed procedure description, surgical time, intra- and post-

operative complications, blood loss, and length of hospital stay)

and a physician-based follow-up assessment were recorded.

Descriptive statistics and multivariate logistic regression were

used to analyze pre to post-operative patient-based VAS values

for leg, VAS for back pain and COMI scores for the whole group

and for four cohorts with differing periods of conservative care.

RESULTS

The duration of previous conservative treatment, stratified as

outlined, did not have any influence on the ultimate outcomes.

68

SUNDAY 21 APRIL 2013The Spine Society of Australia 24th Annual Scientific Meeting 2013


FREE PAPER SESSION 6 | Lumbar • Chair Rob Kuru • 8.30am - 10.00am

There were no statistically or clinically significant differences in leg

pain relief, back pain relief or COMI score for the four different

time periods of conservative care. The individual results for the

groups are for back pain relief: 2.4, 1.9, 1.8, 2.1, 2.4 (p>0.05); for

leg pain relief: 4.0, 3.9, 3.8, 4.1, 4.1 (p>0.05); for COMI: 3.3, 3.2,

3.1, 3.4, 3.4, (p>0.05).

DISCUSSION

Due to spontaneous symptomatic recovery in patients with

lumbar disc herniation, surgical decision making is still a challenge.

This study demonstrated significant improvements in standardized

outcomes following surgical discectomy that were independent

of the duration of conservative care. These findings have to be

confirmed in more controlled study environment.

8.46am | 6.3

THE VISCOELASTIC LP-ESP LUMBAR DISC

PROSTHESIS WITH 6 DEGREES OF FREEDOM:

A PROSPECTIVE STUDY OF 120 PATIENTS WITH

2 YEARS MINIMUM FOLLOW-UP

*Jean Yves Lazennec

Pitié-Salpetrière Hospital, Paris University, France

INTRODUCTION

The viscoelastic lumbar disk prosthesis ESP is an innovative

one-piece deformable but cohesive interbody spacer; it provides

6 full degrees of freedom about the 3 axes including shock

absorption. The prosthesis geometry allows limited rotation and

translation with resistance to motion (elastic return property)

aimed at avoiding overload of the posterior facets. The rotation

center can vary freely during motion. It thus differs substantially

from current prostheses. This study reports the results of a

prospective series of 120 patients who are representative of the

current use of the ESP implant since 2006.

MATERIAL & METHODS

The surgeries were performed by 2 senior surgeons. There were

73 women & 47 men in this group. The average age was 42(27-60).

The average body mass index was 24.2 kg/m2 (18–33). The

implantation was single level in 89% of cases. 134 ESP prostheses

were analyzed. Clinical data and X-rays were collected at the pre-

operative time and at 3, 6, 12, 24, and 36 months post-op. The

functional results were measured using VAS, GHQ 28,ODI, SF-36,

( physical component PCS and mental component MCS. The

analysis was performed by a single observer who was independent

from the selection of patients and from the surgical procedure.

RESULTS

The mean operative time was 92 min (SD: 49 min). The mean

blood loss was 73 cc (SD:162 cc).We did not observe device

related specific complications. All clinical outcomes significantly

improved at every time points when compared to the pre-

operative status (Table 1). In the series, 89% of patients had a

good or excellent result at 3 months, 88% at 6 and 12 months,

and 93% at 24 months.

Table 1

Mean±SD PRE OP 3 MO 6 M 12 M 24 M 36 M

VAS 6.6±1.7 3.7±1.9 3.4±2.1 3.5±2.3 3.4±2.4 3.6±2.5

ODI (%) 47.6±14.6 30.3±17.6 24.5±17.6 21.8±16.3 20.6±17.3 19.5±16.9

GHQ 28 64.2±15.6 52.5±14.7 52.7±15.8 52.2±15.4 50.6±15.4 52.2±14.1

SF 36 PCS% 32.4±34.8 48.4±39 51.9±39.3 55.6±39.8 59±39.2 56.8±39.9

SF 36 MCS% 42.3±34.0 50.8±34.6 52.8±35.6 53±36.3 58.7±34.6 57.9±33.4

Tables 2 and 3 summarize the changes in the radiological

parameters of sagittal balance and the variations of range of

motion (ROM) over time.

Table 2PREOP 3M 6M 12M 24M

Pelvic incidence(PI) 54,8±8

Sacral slope (SS) 40,4±7,2 41±6,6 40,6±6,8 41,2±6,2 41,4±6,8

Pelvic tilt (PT) 14,3±7,3 11,8±7 12,3±6,2 12,4±6,7 12±7

Lumbar lordosis 55,8±10 58,5±12,5 59,2±11,3 59,4±13,5 58,3±13,1

Table 3 3M 6M 12M 24M

ROM of the instrumented level 4,1±2,4 4,7±2,8 6,0±3,4 5,3±3,2

ROM of upper adjacent level 4,9±3,2 6,0±4,7 7,9±5,2 6,2±4,1

ROM of the lumbar spine 24,3±14, 27,9±17,9 34,6±16,3 27,5±17,2

CONCLUSION

The concept of the ESP prosthesis is different from that of the

articulated devices currently used in the lumbar spine. This study

reports encouraging clinical results about pain, function, kinematic

behavior & radiological sagittal balance. Results are in accordance

with previous data collected since the first cases performed in 2005.

69




9.15am | 6.4

IS THERE AN ASSOCIATION BETWEEN ABDOMINAL

MUSCLE MORPHOLOGY AND DEGENERATIVE

SPONDYLOLISTHESIS?

*Tcherveniakov P,1 Fraser RD,1, 3 Freeman BJC ,1, 3 Jones CF 1, 2

1. Adelaide Centre for Spinal Research, SA Pathology,

Adelaide, SA Australia

2. School of Mechanical Enginering, University of Adelaide, SA

Australia

3. Discipline of Orthopaedics and Trauma, School of Medicine,

University of Adelaide, SA Australia

INTRODUCTION

The pathogenesis of degenerative spondylolisthesis is not well

understood, with many etiological factors identified. The aims of

this study were to investigate the contributions of abdominal

muscle and aponeurosis morphology to L4-5 and L5-S1 vertebral

slip and to devise models for the prediction of vertebral slip.

METHODS

Axial abdomino-pelvic computed tomography scans from 200

subjects were examined retrospectively. Those with spondylolysis

were excluded (n=14), and spondylolisthesis was expressed as a

continuous measure in the remaining subjects. Muscle parameters

(abdominal and paraspinal muscle area and density, aponeurosis

width) and bony parameters (vertebral slip, lumbar index, disc

index, facet joint angle) were measured for each vertebral or

intervertebral level. Multiple linear regression analyses were

performed to form six hypothesis-driven and predictive models

for percent vertebral slip.

RESULTS

Increasing lateral abdominal muscle (LAM) area (p=0.01) and

decreasing rectus abdominis muscle (RAM) area (p=0.02) were

significant predictors of vertebral slip at the L5-S1 level. Measures

of aponeurosis width did not contribute to L5-S1 vertebral slip.

Neither muscle morphology or aponeurosis width parameters

were significant predictors of slip at the L4-5 level. More sagittal

facet joint orientation and decreasing lumbar index were also

significant predictors of vertebral slip at both levels in all models.

CONCLUSION

In addition to previously identified osseous factors such as facet

angle (Grobler et al 1993) and lumbar index (Chen and Wei,

2009), this retrospective imaging study shows that abdominal

muscle area may be associated with vertebral slip at the L5-S1

level. The reduction in RAM area may represent increased

musculoaponeurotic laxity, which predisposes to vertebral slip by

lowering intra-abdominal pressure. The association with increased

LAM area may be the result of a compensatory response to

vertebral slip, which increases intra-abdominal pressure to brace

an unstable spine.

REFERENCES

1. CHEN IR, WEI TS

Disc height and lumbar index as independent predictors of

degenerative spondylolisthesis in middle-aged women with

low back pain. Spine 34: 1402-9, 2009.

2. GROBLER LJ, ROBERTSON PA, NOVOTNY JE, POPE MH

Etiology of spondylolisthesis. Assessment of the role played

by lumbar facet joint morphology. Spine 18: 80-91, 1993.

9.23am | 6.5

HISTOLOGICAL CHARACTERISATION OF

TRABECULAR BONE OF THE L4 LUMBAR SPINOUS

PROCESS IN FEMALE PATIENTS UNDERGOING

DECOMPRESSIVE LAMINECTOMY

*1MR Zarrinkalam, A Mulaibrahimovic, AQ Nguyen, R Fraser,

JS Kuliwaba, RJ Moore

ACSR, SA Pathology, SA, Australia

INTRODUCTION

There is limited information about bone quality in the spinal

region of patients with lumbar spinal stenosis. In this study we

characterised the trabecular bone microarchitecture and the

density of osteocytes (cell regulator of bone homeostasis) in

bone of the lumbar spinous process of female patients who

underwent decompressive laminectomy. Thus we hypothesized,

there is:

� a significant difference in bone volume between these patients

� a relationship between the density of osteocyte lacunae and

their canaliculi with the percentage of bone volume / total

tissue volume (BV/TV) in the lumbar spine.

METHODS

Twenty three fresh samples of bone were collected from the

base of the L4 lumbar spinous process in females undergoing

decompressive laminectomy. The bone specimens were scanned by

70




microCT and processed for histology to estimate the total density

of lacunae, as well as the density of empty lacunae using Holmes

Silver staining. 1 Group differences were tested using student’s

t-test and relationships between microarchitectural parameters

and density of lacunae were tested using regression analysis.

RESULTS

The average BV/TV of this cohort was 21.6% and there was

significant variation among these patients. Based on the BV/TV

value, the specimens were divided into two groups:

a) high BV/TV (over 21%) and

b) low BV/TV (below 21%)

There was no significant difference for the density of total lacunae

and of empty lacunae between the two groups. However, the

visual examination of the sections that were stained with

Holmes-Silver impregnation demonstrated that osteocyte

canaliculi were shorter in the low BV/TV group. Furthermore,

there was stronger silver staining of bone tissue in the low

BV/TV group.

CONCLUSION

There was sufficient variation between the BV/TV of the patients

to divide the cohort into osteoporotic and non-osteoporotic

groups. The higher BV/TV was due to a higher trabecular number.

Taken together, the shorter canaliculi in the low BV/TV group

with no observed difference between the low and high BV/TV

groups for density of lacunae, suggest that the function and activity

of osteocytes and not their number are adversely affected in the

low BV/TV group. Stronger silver staining of bone tissue has been

related to a higher level of osteopontin in the bone matrix. 1 High

levels of osteopontin have also been associated with low BMD,

increased levels of bone turnover markers, and osteoporotic

vertebral fractures. 2 Thus, the strong silver staining of the bone

tissue in the low BV/TV group further supports this finding. Further

more, we speculate that patients with low BV/TV could have a

slower bone healing process and longer post-operative recovery.

REFERENCES

1. GAUDIN-AUDRAIN C et al.

Osteopontin is histochemically detected by the AgNOR

acid-silver staining. Histol Histopathol. 2008;23: 469-78.

2. FODOR D et al.

The value of osteopontin in the assessment of bone mineral

density status in postmenopausal women. J Investig Med

2013;61: 15-21.

9.31am | 6.6

THE PATHOPHYSIOLOGY OF MODIC (ENDPLATE)

CHANGES IN THE HUMAN LUMBAR SPINE:

IS THE OSTEOCYTE LACUNAR CELL NETWORK

INVOLVED?

*Kuliwaba JS,1, 2, 3 Perry M,1, 2 Perilli E,3, 4 Parkinson IH,2, 3

Chong KC,2, 5 Fazzalari NL,3 Osti OL 5

1. Adelaide Centre for Spinal Research, SA Pathology, SA Australia

2. Bone and Joint Research Laboratory, SA Pathology, Adelaide, SA

Australia

3. Discipline of Anatomy and Pathology, The University of Adelaide,

SA Australia

4. Medical Device Research Institute, Flinders University, Bedford

Park, SA Australia

5. Calvary Health Care, North Adelaide, SA Australia

INTRODUCTION

The pathophysiological mechanisms underlining the appearance

and progression of Modic changes remain elusive. Our recent

study has shown that:

Modic type 1 changes of the lumbar vertebrae are associated

with elevated bone turnover measured at the bone tissue level;

Modic type 2 changes are linked to reduced bone formation; and

Modic type 3 changes are characterised by a stable sclerotic phase

of the bone pathology (Chong et al. ISSLS 2012:#O235; Perilli et

al. ORS 2010:#1504). Given that the osteocyte lacunar cell

network plays a central role in governing skeletal turnover, the

aim of the present study was to investigate whether Modic

changes associate with a variation in the numerical density of

osteocyte cells and their lacunae.

METHODS

Fourty-one patients (25 men, 16 women; aged 55.0±12.4 years)

underwent elective spinal surgery with lumbar vertebrae showing

Modic changes on pre-operative lumbar MRI. The cases were

subdivided as follows:

Modic 1 (n=9), Modic 2 (n=25), Modic 3 (n=7).

A transpedicular vertebral bone biopsy (25x3mm) was taken in

all patients. Biopsies were resin-embedded for histomorphometric

analysis (H&E; von Kossa /H&E) of numerical density of osteocytes,

empty lacunae, and total lacunae (number per mm2 bone) and

tissue level bone remodelling (erosion surface / bone surface[%],

osteoid surface / bone surface[%]).

71




METHODS

There were no differences between Modic types 1, 2, and 3 for

any of the osteocyte morphometric parameters: osteocyte,

empty lacunar, and total lacunar density, and percent of empty

lacunae relative to total lacunae. Tissue level analysis of bone

remodelling indices revealed less erosion surface in Modic 3 (5.4%)

compared with Modic 1 and 2 (9.7% and 8.6%, respectively).

There was less osteoid surface in Modic 2 (14.0%) compared

with Modic 1 and 3 (22.1% and 18.0%, respectively). The osteoid

surface/erosion surface ratio was highest for Modic 3, indicative

of net increased bone formation. There were no correlations

between osteocyte parameters and bone erosion or osteoid

surface indices.

CONCLUSION

This study has shown that the numerical density of osteocytes,

empty lacunae, and total lacunae in lumbar vertebral bone does

not differ between Modic types. Given that empty lacunae can

provide a tissue level stimulus for bone resorption, it was surprising

to not observe a relationship between empty lacunae (varied

between 10-50%) and bone resorption or formation parameters.

These novel data suggest that osteocyte cell death does not play

a role in the dysregulated bone remodelling associated with

Modic types. Further research investigating the expression of

osteocytic proteins, such as those involved in mechanotransduction,

may identify a role for the osteocyte cell network in the

biomechanical and / or biochemical mechanisms of Modic

changes.

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Free PaperSession 7

CERVICALSunday 21 April | 10.30am - 11.45am



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10.30am | 7.1

THE ROLE AND SAFETY OF THE SITTING POSITION

IN INSTRUMENTED CERVICAL SURGERY

*Gan C,1 Maartens N,2 King J 3

1. The University of Melbourne, Parkville, VIC Australia

2. The Alfred, Prahran, VIC Australia

3. The Royal Melbourne Hospital, Parkville, VIC Australia

INTRODUCTION

Placing patients who are undergoing neurosurgical procedures to

the cervical spine in the sitting position offers significant advantages,

including decreased venous pressure, optimum midline access,

lowered intracranial pressure and a relatively dry surgical field

(Porter et al 1999). These advantages have particular benefit for

certain patient subgroups, however they are largely neglected in

the literature due to concerns of increased risk in venous and

paradoxical air embolism. This study addresses the role and safety

of the sitting position for instrumented cervical surgery.

METHODS

Twenty-five consecutive patients who underwent instrumented

cervical surgery in the sitting position were recruited via

retrospective analysis. All patients were operated on by the same

surgeon between August 2004 and October 2010. The study

was approved by the Office for Research at Melbourne Health.

Patient demographics, length of surgery and complications arising

from the surgical procedure were documented. Venous air

embolism was defined as a decrease in ETCO2 of ≥ 5 mmHgwithin 5 minutes. Hypotension was defined as a reduction in

systolic blood pressure of ≥ 25% from the baseline systolic bloodpressure. Other complications were duly noted when they

occurred.

RESULTS

The average age of patients recruited was 61.1 years old

(standard deviation of 17.1 years) and the average length of

surgery was 234.6 minutes (standard deviation of 102.0 minutes).

The incidence rate of venous air embolism in instrumented

cervical surgery in the sitting position was 0% (97.5% one-sided

confidence interval: 0-13.7%). However, 5 other complications

occurred (incidence rate of 20% with a 95% confidence interval

of 6.8-40.7%). These complications were: the dehiscence of the

posterior wound of a front/back procedure requiring return to

theatre for rostral extension of the instrumentation, a misplaced

lateral mass screw, postoperative meningitis and a cervical cord

contusion with transient hemiparesis caused by sublaminar wires.

CONCLUSION

Previous publications have already reported the safe use of the

sitting position in cervical surgery (Leslie et al 2006). This study

extends the use of the sitting position to more complex cervical

surgical procedures without impacting upon patient safety. Patient

groups potentially benefiting from this position include patients

with spinal cord compression, raised intracranial pressure, morbid

obesity, an unstable spine due to fracture or ankylosing spondylosis

and patients receiving front / back cervical procedures. With

appropriate precautions & patient selection, patients who require

instrumentation are not precluded from being operated on in the

sitting position and are subsequently not denied its advantages.

REFERENCES

1. PORTER JM, PIDGEON C, CUNNINGHAM AJ

The sitting position in neurosurgery: a critical appraisal.

Br J Anaesth. [; Review]. 1999 1999;82(1):117-28.

2. LESLIE K, HUI R, KAYE AH

Venous air embolism and the sitting position: a case series.

J Clin Neurosci. 2006 2006;13(4):419-22.

10.38am | 7.2

CERVICAL SPINAL SAGITTAL ALIGNMENT:

AN ANALYSIS OF YOUNG, ASYMPTOMATIC

VOLUNTEERS

*Wilson PJ,1 Saravanja DD,2, 4 Sergides IG,3, 4 White GJ,4 Sears WR 1,4

1. Neurosurgery, Australian School of Advanced Medicine,


2. Orthopaedics, Australian School of Advanced Medicine,


3. Neurosurgery, Royal North Shore Hospital, Sydney, NSW Australia

4. Research Department, Wentworth Spine Clinic, Sydney, NSW

Australia

INTRODUCTION

Thoracolumbar sagittal balance has attracted substantial recent

research but less attention has been given to the cervical spine.

Comparatively little data exists regarding normal cervical spinal

alignment, especially in young people, and its relationship, if any,

to thoracolumbar sagittal balance. The aims of this study were to

74



FREE PAPER SESSION 7 | Cervical • Chair Justin Pik • 10.30am - 11.45am

create a normative database of cervical sagittal alignment

parameters in young patients and to examine relationships with

parameters of thoracolumbar sagittal balance.

METHODS

The study analysed the cervical spinal alignment in young (20-45

years), asymptomatic volunteers, taken from a larger study of

the whole spines of healthy volunteers, using EOS digital imaging

(Biospace, Paris, France). Subjects had no significant history of

neck or arm pain, nor history of previous spinal surgery. Imaging

of their whole spine and lower limbs was conducted in a neutral

standing position. Three independent observers (a neurosurgical

trainee [PW], an orthopaedic spinal surgeon [DS] and a neuro-

surgeon [IS]) assessed the images for cervical shape (lordotic,

straight, kyphotic or kypho-lordotic) & measured alignment

parameters using Keopsviewer software (SMAIO, Lyon, France).

Inter- & intra-observer reliability was assessed using measurement

of intraclass correlation coefficients (ICCs). Correlations between

variables were assessed using linear regression. Significance was

set at p<0.05.

RESULTS

Fifty-four subjects were assessed. The most commonly observed

cervical shape was straight: 20/54 (37%). 8/54 were lordotic

(14.8%). The remainder were kyphotic or kypho-lordotic.

However, intra- and inter-observer ICCs for ‘cervical shape’

were relatively poor (0.72 & 0.69 respectively). Results of

calculated variables are shown in the table below.

Calculated C0-2 C1-3 C5-7 C2-7 Cervical T1-T12variables angulation angulation angulation angulation angulation kyphosis

Mean -6.0 -21.0 -2.2 -2.9 -20.4 41.1

SD 8.9 7.7 7.7 11.9 8.2 10.3

Table. Calculated values of cervical sagittal balance (degrees,

negative values = lordosis)

Strong negative correlations were found between C2-7 angulation

and T1 superior endplate angle (r = -0.60, p <0.0001), C2-7

angulation and T1-T12 kyphosis (r = -0.57, p < 0.0001), and

between C1-3 angulation and C5-7 angulation (r = -0.50 and

p = 0.0001). No correlation was found between C2-7 angulation

and measures of thoracolumbar sagittal alignment (PRT12, pelvic

incidence or L1-S1 lordosis).

CONCLUSION

Contrary to expectations, only a minority of cervical spines in

this observed population of 20-45 year old asymptomatic

individuals were lordotic. The majority of spines were straight

and several were kyphotic. While cervical lordosis was found to

correlate strongly with thoracic kyphosis and the angle of the T1

superior end-plate, traditional measures of lumbar sagittal balance

appear to be independent of the cervical spine. Further research

is needed to see if this finding also applies to older patients where

it may be important in surgical planning for sagittal deformity

correction. Validated reproducible parameters of cervical sagittal

alignment have been defined from the skull base to thoracic

spine in this series.

11.00am | 7.3

EFFECT OF PLL RESECTION ON THE STABILITY OF

CERVICAL DISC ARTHROPLASTY

*Patwardhan A,1, 2 Tsitsopoulos P,1, 2 Potluri T,2 Zelenakova J,2

Carandang G,2 Phillips F,3 Zindrick M,3 Ghanayem A,1 Havey R,1, 2

Voronov L 1, 2

1. Loyola University Chicago, Maywood Campus, Illinois, USA

2. Edward Hines Jr VA Hospital, Hines, Illinois, USA

3. Rush University Chicago, Illinois, USA

INTRODUCTION

The need for resection of the PLL during disc replacement

surgery has been debated by many. Some advocate partial or

complete resection to achieve a more parallel disc-space

distraction, while others advocate its preservation for

biomechanical stability if its entire removal is not required for

neural decompression. We investigated the effect of PLL resection

on cervical kinematics after disc replacement surgery using a

compressible six degrees of freedom disc prosthesis (M6-C,

Spinal Kinetics, Sunnyvale, CA, USA).

METHODS

Nine cervical spines were tested in flexion-extension (FE) , lateral

bending (LB) and axial rotation (AR) to maximum moments of

±1.5Nm. After intact testing compressible, six-degrees-of-freedom

disc prosthesis was implanted at C6-C7 through wide anterior

discectomy window while leaving uncinate processes and PLL

intact. Finally, PLL was cut while keeping the disc prosthesis in

place. This was accomplished by placing a stainless steel wire

75




looped around PLL after performing discectomy and prior the

TDR insertion. The wire was introduced posteriorly through a

single puncture hole in the ligamentum flavum. Segmental ROM

and stiffness in the high flexibility zone around the neutral

posture were analyzed using repeated measures ANOVA.

RESULTS

With the PLL intact, the FE-ROM was significantly decreased

after insertion of TDR compared to intact (12.6±3.2 to 9.5±2.7

degrees) (p<0.05). PLL Resection increased FE-ROM to10.8±2.7

degrees, closer to intact magnitude (p>0.05). PLL resection did

not affect the ROM in LB or AR (p>0.05). Segmental flexion

stiffness significantly increased after TDR with intact PLL

(0.09±0.05 to 0.17±0.08 Nm/deg) (p<0.05), while after PLL

resection the segmental flexion stiffness (0.13±0.07 Nm/deg)

was closer to the intact level (p>0.05).

CONCLUSIONS

PLL resection resulted in a significant increase of ROM (1.3

degrees or 16%) without compromising segmental stiffness. It

also facilitataes a more parallel disc-space distraction without

substaially increasing lordosis, as a result maintaining correct

cervical saggital balance. Further studies with other implant

designs are needed to fully understand the role of PLL in TDR

kinematics.

11.08am | 7.4INCIDENCE OF ADJACENT LEVEL OSTEOPHYTES

AFTER ANTERIOR CERVICAL DISCECTOMY AND

FUSION USING NON-PLATE FIXATION

*Kumar A, Ahuja S

The Cardiff Spine Unit, University Hospital of Wales, Cardiff, UK

INTRODUCTION

Formation of osteophytes at adjacent levels (ALOD) after anterior

cervical discectomy and plating (ACDF) is a well-documented

phenomenon. Various theories have been proposed to explain

this including stripping of the anterior longitudinal ligament, use

of Caspar pins and the use of anterior cervical plates. Placement

of plates within 5 mm of the endplate in particular, has been

implicated as the chief reason for ALOD1. ACDF without use

of plates has consequently shown to reduce the incidence of

ALOD. Plate fixation shows a favourable fusion rate for ACDF

at 2 levels or more. Therefore alternate fixation techniques for

ACDF without using plates have been developed (Zero-P,

Coalition). We present a series of cases of ACDF with fixation

using these non-plate techniques focussing on ALOD.

MATERIALS & METHODS

This is a retrospective radiological study. We included consecutive

patients undergoing ACDF with a non-plate devices. We included

both single level and 2 level ACDFs. We excluded patients

without a minimum follow-up of 6 months. Assessment of done

with standard cervical spine xrays in the antero-posterior and

lateral planes.

RESULTS

A total of 21 patients were identified during this period. After

excluding patients with less than 6 months follow-up, we had 11

patients with a mean follow-up of 12.9 months (6-20). Of these,

7 were 2 level procedures and 4 were single ACDFs. 9 patients

had the Zero-P implant and 2 had the Coalition used. None of

these 11 patients developed adjacent level osteophytes during

this study period.

CONCLUSIONS

Eliminating the use of plates in ACDF can reduce ALOD. In case

of ACDF at more than 2 levels, biomechanical stability to improve

fusion rates can be achieved using non-plate fixation implants.

REFERENCE

1. PARK JB, CHO YS, RIEW KD, 2005.

Development of adjacent-level ossification in patients with an

anterior cervical plate. JBJS Am., 87(3), pp.558-63.

76




11.16am | 7.5ANTERIOR FIXATION AND RECONSTRUCTION

FOR SUBAXIAL CERVICAL SPINAL INJURIES:

REASONS FOR FAILURE

*N Verghese, M McCarthy, O Jenkins, R Williams

Orthopaedic Spinal Surgery, Princess Alexandra Hospital,


INTRODUCTION

Anterior cervical fixation is commonly employed for subaxial

instability, although previous studies suggest loss of fixation in

managing certain injury patterns. 1 The aim of this study is to

identify the rate and mode of failure of anterior cervical fixation

in a large cohort of patients treated for subaxial cervical instability.

METHODS

A retrospective review of consecutive patients treated by anterior

or antero-posterior cervical fixation over a 5 year period was

undertaken. All patients were followed for a minimum of 8

weeks. Injury characteristics (level of injury, type of injury, 2 fixation

type, discectomy vs. corpectomy, type of graft, supplementary

stabilization methods) were recorded and all relevant imaging

was reviewed to assess operative technique. Postoperative

imaging was assessed for early failure (defined as change in angular

kyphosis > 11 degrees, translation of >3.5mm), radiographic

screw loosening or frank failure within the first 8 weeks. Technical

surgical errors such as overdistraction (opening of disc and facet

joint space to greater than segments above and below) and failure

to restore lordosis were also noted. Radiographs were reviewed

by 2 separate observers who agreed on all the failures and

technical errors.

RESULTS

One hundred and seventy patients with subaxial cervical spine

injuries were identified, of whom 112 comprised the study co-

hort. 80% of subjects were male, mean age was 37 yrs. (SD +/-

16.9) and mean follow-up was 32 weeks (SD +/- 35.9). The

majority of injuries were facetal fractures, with or without

dislocation (42 unilateral, 40 bilateral). There were 25 vertebral

body fractures and 5 other fracture patterns. Early postoperative

failure of fixation was identified in 20 cases, of which 18 related

to anterior cervical discectomy and fusion (ACDF) and two were

associated with cervical corpectomy. There was no failure of

reconstruction in the antero-posterior fixation group. Ten of the

failed ACDF procedures required reoperation with the remainder

treated non-operatively. A further 6 cases required additional

procedures for reasons of operative technique or fracture

configuration unrelated to fixation. Increasing age was significantly

associated with reoperation after initial anterior fixation

(Wilcoxon rank sum test, p < 0.05). Early loss of fracture position

also correlated with presence of end plate fractures (Pearson x2

test) and was more common in bifacetal and lower cervical

injuries from C6 – C7/T1 although not statistically significant.

CONCLUSIONS

Anterior cervical fixation is a successful technique in the

management of subaxial injuries. Caution should be exercised in

older patients, in those with lower cervical or bilateral facetal

disruption or with concomitant end plate and/or facetal fractures.

Technical errors such as overdistraction and failure to restore

lordosis may also be associated with early failure of fixation.

REFERENCE

1. MICHAEL G JOHNSON, CHARLES G FISHER, MICHAEL BOYD,

TOBIAS PITZEN, MD, THOMAS R OXLAND,

MARCEL F DVORAK

The Radiographic Failure of Single Segment Anterior Cervical

Plate Fixation in Traumatic Cervical Flexion Distraction Injuries.

Spine 2004; 29 (24):2815–2820.

77




78

Notes and Questions



PosterPresentations

79

24

1. EPIDEMIOLOGICAL TRENDS OF SPINE TRAUMA:

AN AUSTRALIAN LEVEL 1 TRAUMA CENTRE STUDY

Jin Tee

Neurosurgery Trainee, The Alfred Hospital, Melbourne, VIC Australia

INTRODUCTION

Knowledge of current epidemiology and spine trauma trends

assists in public resource allocation, fine-tuning of primary

prevention methods and benchmarking purposes.

METHODS

Data on all trauma patients with spine injuries admitted to the

Alfred Hospital, Melbourne between 1 May 2009 and 1 January

2011 were collected from the Alfred Trauma Registry, Alfred Health

medical database and Victorian Orthopaedic Trauma Outcomes

Registry (VOTOR). Epidemiological trends were analyzed as a

general cohort, and comparison cohorts of non-survivors versus

survivors and elderly versus non-elderly. Linear regression analysis

was utilized to demonstrate trends with statistical significance.

RESULTS

There were 965 trauma patients with spine injuries with 2333

spine trauma levels. The general cohort showed a trimodal age

distribution, male to female ratio of 2.2, motor vehicle accidents

as the primary spine trauma mechanism, 47.7% patients with

severe polytrauma as graded using the Injury Severity Score

(ISS), 17.3% suffering traumatic brain injury (TBI), the majority of

patients suffering from one spine injury level, 7% neurological

deficit rate, 12.8% spine trauma operative rate and 5.2% mortality

rate. Variables with statistical significance trending towards

mortality were the elderly, motor vehicle occupants, severe ISS,

TBI, C1/2 dissociations and ASIA A, B and C neurological grades.

Variables with statistical significance trending towards the elderly

were females, low falls, one spine injury level, Type 2 odontoid

fractures, subaxial cervical spine distraction injuries, ASIA A, B and

C neurological grades and patients without neurological deficits.

Of the general cohort, 50.3% of spine trauma survivors were

discharged home and 48.1% discharged to rehabilitation facilities.

CONCLUSION

This study provides baseline spine trauma epidemiological data.

The trimodal age distribution of trauma patients with spine

injuries calls for further studies and intervention targeted towards

the 46 to 55 years age group as they represent the main providers

of financial and social security. The study’s unique feature of

delineating variables with statistical significance trending towards

both mortality and the elderly also provides useful data to guide

future research studies, benchmarking, public health policy and

efficient resource allocation for the management of spine trauma.

Key words:

spine trauma, epidemiology, demographics, spinal injury

characteristics, neurological status, registry, prevention.

2. CERVICAL SPINAL CORD INJURY AT THE

VICTORIAN SPINAL CORD INJURY SERVICE:

THE LAST DECADE

*Nathan G Myhill, Simon C Lau, Rekha Ganeshalingam, Gerald Quan

Victorian Spinal Cord Injury Service, Austin Hospital, Heidelberg,

VIC Australia

INTRODUCTION

Cervical Spinal Cord Injury (CSCI) is a significant medical and

socioeconomic problem. In Victoria, Australia, there has been

limited research into the incidence of CSCI. The Austin Hospital

and Victorian Spinal Cord Injury Service (VSCIS) is a tertiary

referral hospital that accepts referrals for surgical management and

ongoing neurological rehabilitation for south eastern Australia.

METHODS

This was a retrospective review of medical records from January

2000 to January 2010 of all patients who underwent surgical

management of acute CSCI in the VSCIS catchment region.

Outcome measures included: demographics, method of injury

and associated factors (like alcohol) and neurological status

RESULTS

Men were much more likely to have CSCI than women with a

4:1 ratio, and the highest incidence of CSCI for men was in their

20s, who were at greater risk of complete injury. The most

common cause of CSCI was transport related (51%), followed

by falls (20%) and water-related incidents (16%). Falls were more

prevalent among those >50 years. Alcohol was associated in 22%

of all CSCIs, including 42% of water related injuries. Water

related injuries only involved people <50 years.

CONCLUSION

Our retrospective epidemiological study identified at-risk groups

presenting to our spinal injury service. Young males in their 20s

were associated with an increased risk of transport related

80



POSTER PRESENTATIONS

accidents, water related incidents in the summer months and

accidents associated with alcohol. Another high risk group were

men >50 years who suffer falls from height. Public awareness

campaigns should target these groups to lower incidence of CSCI.

3. NON-INVASIVE LUMBAR SPINE MOVEMENT:

VALIDATION OF THE MOTIONSTARTM 3D

ELECTROMAGNETIC TRACKING SYSTEM AND

PRELIMINARY EVIDENCE

*Kevin Singer, Aubrey Monie, Roger Price

School of Surgery, The University of Western Australia, Nedlands, WA

Australia

INTRODUCTION

Disturbed movements of the lumbar spine can provide ‘signatures’

to underlying pathology and will usually differ from normal patterns

in terms of quality and range. Non-invasive spine movement

assessment using 3-D motion tracking systems discriminates

normal from symptomatic subjects1, and may help to triage

pathology subgroups. System validation is a necessary prerequisite

to ensure reliable data acquisition in clinical studies.

METHODS

The MotionStarTM 3-D tracking device [Ascension Technology,

VT, USA] records displacement coordinates at 50Hz in the three

cardinal planes. A custom triaxial protractor with a known accuracy

of 0.5° was designed for replicate trials to simulate the normal

range of human lumbar movement. Data from 10 trials for

displacements: 0–10°, 0–30° and 0–60°, in each axis [X,Y&Z],

were derived. Normal volunteers [n=10] were assessed to map

the coupled movement patterns for : flexion (F), side-flexion (SF)

and extension (E), to establish reliability from 10 repeat trials and

define a preliminary reference range.

RESULTS

The Coefficients of Variation [CV%] for each triaxial protractor

trial series, across all end-points and axes, ranged between 0.001

– 0.14%. Preliminary data for asymptomatic volunteers showed

F>SF>E with ranges equivalent to published data for non-invasive

lumbar range of motion. Repeatability trials produced CVs <5%

CONCLUSION

The MotionStarTM 3-D motion tracking system demonstrated

low system error across all ranges using a triaxial protractor

standard. Preliminary assessment of variability within subject data

was acceptable and preliminary normal reference ranges were

consistent with published data for lumbar movement.

REFERENCE

1. BARRETT CJ, SINGER KP, DAY R

Assessment of combined movements of the lumbar spine in

asymptomatic and low back pain subjects using a three-

dimensional electromagnetic tracking system. Man Ther. 1999

4(2):94-9.

4. “PONSETI” FOR CONGENITAL KYPHOSIS

*Kumar A, McGrath S, Dillon D

Royal Perth Hospital, Perth, WA Australia

INTRODUCTION

The estimated prevalence of vertebral malformations is

approximately 0.5 to 1 in 1000. Congenital kyphosis is far less

common than congenital scoliosis. The deformity is caused by

developmental anomalies that impair longitudinal growth anterior

or anterolateral to the transverse axis of vertebral rotation in the

sagittal plane.

Winter et al concluded that congenital kyphosis is progressive

without surgical intervention. Paralysis is related to growth and

deformity. It usually presents during the adolescent growth spurt

phase and is progressive unless the deformity is treated.

Traditionally the recommended treatment for congenital kyphosis

was early fusion surgery with or without correction. Non-operative

treatments were not considered effective in preventing the

deformity. Surgical treatments, however, are fraught with risks

given the nature of the anatomy.

MATERIALS & METHODS

We present a series of children presenting with kyphotic

deformities of the spine who were treated in our unit non-

operatively with casting and bracing. 1 was female and 3 males. 2

involved the cervical spine and 2 involved the thoraco-lumbar spine.

2 were type 1, 1 was type 3 and 1 was of type 4 as per the 3D

classification system (Kawakami, Spine 2009). The average age at

presentation was 4 years. The average time in brace was 9.5 months

with 2 still being treated in a brace. There was complete correction

obtained in the 2 who have completed treatment in brace.

81




Poster 4 continued

CONCLUSION

We recommend the use of casting and bracing in a carefully

selected group of children with congenital kyphotic deformities.

With appropriate bracing and close follow-up, we believe that

the progress of these deformities can be slowed down or

corrected allowing greater skeletal maturity before surgical

treatment is indicated. We even believe that in a small subgroup,

bracing may be the only treatment required.

5. THE LESS INVASIVENESS OF CERVICAL

POSTEROLATERAL APPROACH FOR PEDICLE

SCREW FIXATION USING NAVIGATION SYSTEM

*Doi H, Tokioka T

Department of Orthopaedic Surgery, Kochi Health Sciences Center,

Kochi, Japan

INTRODUCTION

The cervical pedicle screw (CPS) provides greater mechanical

strength than fixation by other methods but has a potential risk

to the neurovascular system, especially to vertebral artery (VA).

One of the main reasons to make lateral misplacement of CPS is

difficulty in keeping enough oblique angle to insert CPS because of

being disturbed by muscles and soft tissues in conventional median

approach. To avoid lateral misplacement of CPS we applied new

posterolateral approach for stabilizing cervical vertebral body.

MATERIALS & METHODS

CPSs were used for cervical fractures in 13 cases. 44 CPS from

C2 to Th2 were used. The mean age of the patients was 58

years. Longitudinal posterolateral small skin incision was made

and CPS was inserted using intraoperative CT (Iso-C 3D)

navigation system. Trapezius and intrinsic back muscles were

divided bluntly. After the insertion of CPS, iliac bone grafting was

also performed on the posterior surface of lamina. We analyzed

bleeding volume, surgical time and complications after operation.

CPS placement was examined by CT scan after operation.

RESULTS

The mean bleeding volume was 103ml and the mean surgical

time was 170 min. No complication and no lateral CPS

misplacement were occurred. Only one CPS were deviated

medially (2.3%) but had no complication of neurovascular system.

DISCUSSION

To be able to keep correct oblique angle of CPS insertion

without being disturbed by soft tissues leads to no lateral

deviation that causes VA injury. Navigation system leads us to

correct position of CPS insertion point of cervical lateral mass

easily. The bleeding volume of this approach seems to be less than

that of conventional median approach. Intrinsic cervical muscles

are split and attachments of the muscles are preserved, so this

posterolateral approach may reduce the pain after operation.

CONCLUSION

This new posterolateral approach has the advantage to reduce

vertebral artery injury.

6. MYELOPATHY FROM EXTENSIVE SPINAL

GANGLIONEUROMAS

*Maartens N, Kadota Y

Department of Neurosurgery, Alfred Hospital, Melbourne, VIC Australia

INTRODUCTION

Spinal tumours arising in the intradural extramedullary space

include schwannomas, neurofibromas and ganglioneuromas.

These tumours may be sporadic, often presenting in the fifth to

seventh decades, or they may be a manifestation of an inherited

disorder. They occasionally grow extradurally into the spinal canal,

forming a “dumbbell” shaped appearance.

Ganglioneuromas are rare, slow-growing benign tumours

originating from autonomic ganglia. The spine is an infrequent

location for ganglioneuromas, and when they do occur, they

tend to be unilateral single lesions. The association with

neurofibromatosis type 1 (NF1) is also extremely uncommon.

METHODS

This is a case report describing a unique and dramatic case of

extensive, bilateral spinal ganglioneuromas in a patient presenting

with myelopathy.

RESULTS

A 62 year old right-handed Austrian tax officer presented with a

six-month history of falls and deterioration in fine motor skills.

On examination, he was myelopathic but with only minimal

reduction in power globally (4+/5). He was hypertensive and

six café au lait spots were noted on his skin, but no other

manifestations of neurofibromatosis were found. His family history

82




is unremarkable. MRI of his full spine revealed bilateral intradural

extramedullary nerve root lesions at every level in his spinal

column with the largest in the cervical spine, extending into the

extradural space causing severe canal stenosis.

The patient underwent a C3-6 decompressive cervical laminectomy

and excision of two of the largest lesions, with alleviation of his

symptoms. Histopathology demonstrated spinal ganglioneuromas.

The specimen was then stained for succinate dehydrogenase A

and B, which were normal, rendering germline mutation unlikely.

CONCLUSIONS

Ganglioneuromas of the cervical spine causing cord compression

are rare, with only twelve previously published case reports. Six

of these reports were of ganglioneuromas at multiple sites. This

is only the second report of ganglioneuromas at all cervical,

thoracic and lumbar levels. When ganglioneuromas arise at multiple

locations, it raises the suspicion of NF1. In the six reported cases

of multiple ganglioneuromas, four occurred in patients with NF1.

The one previous case of multiple ganglioneuromas of the entire

spine did not fulfil the diagnostic criteria for NF1, however the

patient was found to have a germline mutation of NF1 on

molecular testing. Therefore a possibility is raised that germline

mutations may account for those patients with some but not all

features of NF1 who present with multiple spinal tumours.

7. SURGICAL PROCEDURES OF ANTERIOR

TRANSARTICULAR FIXATION OF ATLANTOAXIAL

JOINT USING ISO-C 3D NAVIGATION SYSTEM

*Tokioka T, Doi H

Department of Orthopaedic Surgery, Kochi Health Sciences Center,

Kochi, Japan

INTRODUCTION

Barbour has first described anterior transarticular screw fixation

of C1-2 used to stabilize the lateral atlantoaxial joint in patients

with odontoid fractures in 1971. Nevertheless, this technique

seemed to be neglected because it was too difficult to decide

the entry points of ATS screws. Nowadays computer navigation

system and intraoperative CT-imaging is supposed to increase

the accuracy of screw placement. Purpose of this study is to

describe and evaluate a new technique for anterior transarticular

fixation (ATS) of atlantoaxial joints using Iso-C 3D computer

navigation system by analyzing radiographic and clinical outcomes.

METHODS

Anterior transarticular fixation of atlantoaxial joint was performed

with computer navigation system of Iso-C 3D in four cases, three

cases had unstable odontoid fracture with severe osteoporosis

and one suffered from C1/2 subluxation of rheumatoid arthritis

(RA). Age at operation ranged from 69 to 93, averaged 82.5 years

old. One of three odontoid fractures showed Frankel C spinal

cord injury. Before starting of surgery, patients were put on

carbon table with Mayfield three points skull fixator and posture

-reduction of atlantoaxial displacement was achieved under

lateral fluoroscopic viewing. Surgical approach was started from

right anterior neck. Referential frame for navigation system was

fixed on Mayfield fixator, and two cases were failed to fix the

right AA joint only from right anterior neck. Last case was added

a small transverse skin incision about 2 cm on left anterior neck

and put a lag screw in the right AA joint.

RESULTS

A total of 6 transarticular screws and 3 odontoid screws were

placed correctly on postoperative CT scans. Two cases fixed in

bilateral AA joints obtained a good bony union. A 87-year old

female of unstable type Ⅱ odontoid fracture fixed with unilateralatlantoaxial fixation and odontoid screw fixation was resulted in

non-union and salvaged by posterior transarticular fixation.

Postoperative dysphagia occurred and disappeared in a case of

RA with in 4 weeks. There were no other complications such as

vertebral artery injuries, dural tears, or even spinal cord injuries.

CONCLUSION

ATS could be considered a viable option in cases of elderly

osteoporotic odontoid fracture where vascular and osseous

anomalies contradict a bilateral posterior fixation.

REFERENCES

1. BARBOUR JR

Screw fixation in fractures of the odontoid process

S Aust Clinics 1971; 5: 20-24

2. KOLLER H, KAMMERMEIER V, ULBRIHT et al

Anterior retropharyngeral fixation C1-2 for stabilization of

atlantoaxial instabilities: study of feasibility, technical description

and preliminary results. Eur Spine J 2006; 15:1326-1338

3. WANG J, ZHOU Y ZHANG Z, et al :

Minimally invasive anterior transarticular screw fixation and

microendoscopic bone graft for atlantoaxial instability.

2012; 21:1 568-1574.

83




84



Annual Meetings

Year President Date / Site / Guest(s)

1990 Prof Robert Fraser 14 - 15 JULY | Royal North Shore Hospital, Sydney, NSW

Dr Henry Bohlman

Dept of Orthopedic Surgery, Case Western Reserve University, Cleveland, Ohio, USA

1991 Prof Robert Fraser 4 - 5 JUNE Australian Academy of Sciences, Canberra, ACT

1992 Prof Robert Fraser 8 - 9 AUGUST | Adelaide Festival Centre, Adelaide, SA

Dr Daniel ChopinCentre d’Etude et de Traitement des Affections du Rachis, Institut Calot, Berck-sur-mer, France

Dr John O’BrienDept of Spinal Disorders, Robert Jones & Agnes Hunt Orthopaedic Hospital, Oswestry, Shropshire,UK

Dr Arthur SteffeeDivision of Orthopaedics, Cleveland Spine & Arthritis Center,Lutheran Medical Center, Cleveland Medical Center, Cleveland, Ohio, USA

1993 Prof Michael Ryan 26 - 27 JUNE | Hyatt Hotel, Coolum, QLD

Dr Stephen EssesDept of Orthopedic Surgery Baylor College of Medicine, Houston, Texas, USADr James WeinsteinDept of Orthopedic Surgery, University of Iowa, Iowa City, Iowa, USA

1994 Prof Michael Ryan 14 - 15 MAY | RACS, Melbourne, VIC

Dr Gunnar Andersson

Dept. of Orthopedic Surgery, Rush-Presbyterian-St Luke’s Medical Center, Chicago, Illinois, USA

1995 Assoc Prof Bruce McPhee 18 - 22 SEPTEMBER | Combined SSA/NSA Meeting | Cable Beach Resort, Broome, WA

Dr Tom Zdeblick

Dept of Orthopaedic Surgery, University of Wisconsin, Madison, Wisconsin, USA

1996 Assoc Prof Bruce McPhee 13 - 15 SEPTEMBER | Cairns Convention Centre, Cairns, QLDDr Iain McCall

Dept of Radiology Robert Jones and Agnes Hunt Orthopaedic Hospital Oswestry, Shropshire, UK

1997 Dr Richard Vaughan SEPTEMBER | Sanctuary Cove, Gold Coast, QLD

1998 Dr Richard Vaughan SEPTEMBER | Queenstown, NZ

Prof H. Alan Crockard

The National Hospital for Neurology and Neurosurgery, Queen Square, London, UK

1999 Dr Ian Torode SEPTEMBER | Coffs Harbour, NSW

85



Annual Meetings


2000 Dr Ian Torode Adelaide Festival Centre, Adelaide, SA

Dr Howard An

Dept of Orthopdeic Surgery, Rush-Presbyterian-St Luke’s Medical Center, Chicago, Illinois, USA

2001 Dr Barrie Slinger 27 - 29 APRIL | The Esplanade Hotel, Fremantle, WA

Dr Frank Eismont

Dept of Orthopedics and Rehabilitation, University of Miami School of Medicine, Miami, Florida, USA

2002 Dr Barrie Slinger 26 - 28 APRIL | Hilton Hotel, Melbourne, VIC

Dr Randy Davis John Hopkins University Baltimore, Maryland, USA

2003 Prof Nigel Jones 25 - 27 APRIL | Canberra Hyatt, Canberra, ACT

Prof Bernard George Dept of Neurosurgery Dublin, Eire

2004 Prof Nigel Jones 16 - 18 APRIL | Hyatt Hotel, Coolum, QLD

Prof Ciaran Bloger National Centre of Neurosurgery, Dublin, Eire

Prof Robert Gunzburg Free University of Brussels, Antwerp, Belgium

2005 Dr Ian Farey 14 - 17 APRIL | Auckland Hilton Hotel, Auckland, NZ

Dr John Hellier Emory Spine Center, Dept of Orthopaedic Surgery

Emory University School of Medicine, Atlanta, Georgia, USA

2006 Dr Ian Farey 28 - 30 APRIL | Sofitel Wentworth Hotel, Sydney NSW

Dr Alexander Vaccaro Dept of Othopaedic Surgery, Rothman Institute,

Thomas Jefferson University, Philadelphia, Pennsylvania, USA

2007 Dr Roy Carey 20 - 22 APRIL | Hotel Grand Chancellor, Hobart, TAS

Prof Eugene Carragee

Dept of Orthopaedic Surgery, Stanford University School of Medicine, California, USA

2008 Dr Roy Carey 18 - 20 APRIL | Hilton Adelaide, Adelaide, SA

Prof Dieter Grob

Schulthess Klinik, Bern, Switzerland

2009 Dr Peter McCombe 17 - 19 APRIL | Sofitel Hotel, Brisbane, QLD

Dr Marcel Dvorak, Dr Charles Fisher, Dr Tom Oxland

University of British Columbia, Vancouver, Canada

86



Annual Meetings


2010 Dr Peter McCombe 9 - 11 APRIL | Christchurch Convention Centre, Christchurch, NZ

Prof Paul Anderson Dept of Orthopaedics, University of Wisconsin-Madison

Dr Adam La Caze School of Pharmacy, University of Queensland, Brisbane, Qld

Prof Kerrie Mengersen Dept of Statistics, QUT, Brisbane, Qld

Dr Paul Mernagh Health Economics Manager, Health Technology Analysts, Sydney, NSW

2011 A/Prof Graeme Brazenor 15 - 17 APRIL | Sofitel Melbourne on Collins, Melbourne, VIC

Prof Jean-Charles Le Huec Orthopaedic Dept University of Bordeaux Hospital, France

A/Prof Chris Ames Neurosurgery Dept, University of California, San Francisco, USA

Prof Avinash Patwardhan Dept of Orthopaedic Surgery & Rehabilitation, Loyola University

Stritch School of Medicine, Chicago, Illinois, USA

A/Prof Jacqui Close Geriatrician, Prince of Wales Hospital, Sydney, NSW, Australia

Prof Rachelle Buchbinder Monash Clinical Epidemiology Dept, Cabrini Hospital, Melbourne, Vic

2012 A/Prof Graeme Brazenor 27 - 29 APRIL | The Westin Sydney, Sydney, NSW

Dr Choll Kim Minimally Invasive Spine Center, Spine Institute of San Diego, Calif. USA

Dr Pierce Nunley Spine Institute of Louisiana, Shreveport, Louisiana, USA

Dr Jeffrey Roh Seattle Minimally Invasive Spine Center, Seattle, Washington, USA

Prof William Walsh University of New South Wales Orthopaedic Research Laboratories,

Prince of Wales Hospital, Randwick, NSW Australia

2013 Dr Peter Wilde 19 - 21 APRIL | Pan Pacific Perth Hotel, Perth, WA

Prof Michael Fehlings Krembil Neuroscience Center Spinal Program, Toronto Western Hospital

& Neurosurgery Dept, University of Toronto, Toronto, Canada

A/Prof Brian Kwon Department of Orthopaedics, University of British Columbia & Spinal

Surgery, Vancouver General Hospital, British Colombia, Canada

A/Prof Stuart Hodgetts Spinal Cord Repair Lab, School of Anatomy & Human Biology,

University of Western Australia, Perth, WA Australia

Free Paper Session 2

2.1 EARLY PREDICTORS OF FUNCTIONAL DISABILITY

FOLLOWING SPINE TRAUMA: A LEVEL 1 TRAUMA

CENTER STUDY Jin Tee

I was supported by the SWIRE Alfred Spine Trauma

Research Fellowship Award (2012)

2.6 LATERAL MASS AND FACET JOINT INJURIES OF THE

SUBAXIAL CERVICAL SPINE: ASSESSMENT OF

ACCURACY AND INTEROBSERVER AGREEMENT

USING PLAIN RADIOGRAPHS AND COMPUTED

TOMOGRAPHY Brian Freeman

The study was part funded by AOSpine Australia and

New Zealand


3.1 ACTIFUSE IS COMPARABLE TO INFUSE IN ACHIEVING

FUSION Paul Licina

Research funded by Baxter Healthcare (UK). M Johnston

funded by Queensland Orthopaedic Research Trust

3.2 BIOLOGICAL PERFORMANCE OF A POLYCAPROLAC

TONE-BASED SCAFFOLD PLUS RECOMBINANT

HUMAN MORPHOGENETIC PROTEIN-2 (RHBMP-2) IN

AN OVINE THORACIC INTERBODY FUSION MODEL

Mostyn Yong

This study was partially funded by the Queensland

Orthopaedic Research Trust

3.3 BIOMECHANICAL CHARACTERISTICS OF AN

INTEGRATED CERVICAL INTERBODY FUSION DEVICE

Leonard Voronov

Stocks: Spinal Kinetics

Consulting: Alphatec, Aesculap

Speaking / Teaching

arrangements: Aesculap

Trips / Travel: Spinal Kinetics, Aesculap;

SAB: Ortho Kinematics, Axiomed,

Spinal Kinetics

Research Support: Department of Veterans Affairs;

Grants: NIH-NCOMP


4.3 ESTABLISHMENT OF A NOVEL IN VIVO MOUSE

MODEL OF SPINAL CANCER CAUSING EVOLVING

PARAPLEGIA Gerald Quan

This study was supported by the National Health and

Medical Research Council and an Austin Medical Research

Foundation Grant-in-Aid. Seed funding for the establishment

of the Spinal Biology Research Laboratory, University of

Melbourne, was generously donated by Depuy Johnson &

Johnson, Medtronic, Synthes and Stryker.

4.4 WHAT IS THE MOST CONSISTENT MEASURE OF

THORACOLUMBAR SPINAL SAGITTAL BALANCE?

AN ANALYSIS OF HEALTHY VOLUNTEERS AGED 20-45

Peter Wilson

Dr Peter Wilson received a research scholarship from

Medtronic for 2012 totalling $50,000. Mr Gavin White is a

consultant for Medtronic. Mr William Sears is a consultant

for Medtronic and Paradigm Spine.


5.1 BIOMECHANICAL COMPARISON OF ANTERIOR AND

LATERAL PLATING AFTER INTERBODY FUSION USING

A NOVEL SYNTHETIC SPINE MODEL Jonathon Ball

Implants (K2M) for testing were supplied by

LifeHealthCare Spine.


6.4 IS THERE AN ASSOCIATION BETWEEN ABDOMINAL

MUSCLE MORPHOLOGY AND DEGENERATIVE

SPONDYLOLISTHESIS? Petar Tcherveniakov

None of the authors have financial disclosures to declare

that are relevant to this study.

6.6 THE PATHOPHYSIOLOGY OF MODIC (ENDPLATE)

CHANGES IN THE HUMAN LUMBAR SPINE: IS THE

OSTEOCYTE LACUNAR CELL NETWORK INVOLVED?

Julia Kuliwaba

Dr KC Chong, clinical research fellow in spine surgery, was

sponsored by a grant from DePuy Johnson and Johnson

(Australia).

87



Author Disclosures


7.2 CERVICAL SPINAL SAGITTAL ALIGNMENT: AN

ANALYSIS OF YOUNG, ASYMPTOMATIC VOLUNTEERS

Peter Wilson

Dr Peter Wilson received a research scholarship from

Medtronic for 2012 totalling $50,000. Mr Gavin White is a

consultant for Medtronic. Mr William Sears is a consultant

for Medtronic and Paradigm Spine.

7.3 EFFECT OF PLL RESECTION ON THE STABILITY OF

CERVICAL DISC ARTHROPLASTY Avinash Patwardhan

Stock Ownership: Spinal Kinetics (10,000 shares)

Consulting: Alphatec, Aesculap

Speaking / Teaching

arrangements: Aesculap

Trips / Travel: Spinal Kinetics, Aesculap

SAB: Ortho Kinematics, Axiomed,

Spinal Kinetics

Research Support: Department of Veterans Affairs

Grants: NIH-NCOMP

Poster 1 EPIDEMIOLOGICAL TRENDS OF SPINE TRAUMA:

AN AUSTRALIAN LEVEL 1 TRAUMA CENTRE

STUDY

Jin Tee

I was supported by the SWIRE Alfred Spine Trauma

Research Fellowship (2012)

88



Author Disclosures Poster Disclosures

Spine Society of Australia

24th Annual Scientific Meeting

19 - 21 April 2013


Acute spinal cord injury:

Current and future treatments

2424 Spine Society of Australia

c/- the Australian Orthopaedic Association

Level 12 | 45 Clarence Street, Sydney NSW 2000

P +61 2 8071 8000 | F +61 2 8071 8002

E [email protected] | W www.spinesociety.org.au

SSA Conference Secretariat: DC Conferences Pty Ltd

PO Box 637, North Sydney 2059

P +61 2 9954 4400 | F +61 2 9954 0666

E [email protected] | W www.dcconferences.com.au/ssa2013

CO

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The Spine Society of A

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24 - dc conferencessurgical research (2006), the leon wiltse award from the north american spine...

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